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Common Weakness Enumeration

CWE-208

Allowed

Observable Timing Discrepancy

Abstraction: Base · Status: Incomplete

Two separate operations in a product require different amounts of time to complete, in a way that is observable to an actor and reveals security-relevant information about the state of the product, such as whether a particular operation was successful or not.

359 vulnerabilities reference this CWE, most recent first.

GHSA-C9G9-V2J9-8FFV

Vulnerability from github – Published: 2026-07-20 09:31 – Updated: 2026-07-20 21:31
VLAI
Details

Crypt::Password versions through 0.28 for Perl are susceptible to timing attacks.

The check_password method uses the built-in eq operator. This allows discrepancies in timing to be used to guess the underlying hash.

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2026-6656"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-208"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-20T07:16:42Z",
    "severity": "HIGH"
  },
  "details": "Crypt::Password versions through 0.28 for Perl are susceptible to timing attacks.\n\nThe check_password method uses the built-in eq operator. This allows discrepancies in timing to be used to guess the underlying hash.",
  "id": "GHSA-c9g9-v2j9-8ffv",
  "modified": "2026-07-20T21:31:44Z",
  "published": "2026-07-20T09:31:08Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-6656"
    },
    {
      "type": "WEB",
      "url": "https://metacpan.org/release/DRSTEVE/Crypt-Password-0.28/source/lib/Crypt/Password.pm#L190-193"
    },
    {
      "type": "WEB",
      "url": "https://rt.cpan.org/Ticket/Display.html?id=180162"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2026/07/20/4"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-CVW2-XJ8R-MJF7

Vulnerability from github – Published: 2021-03-09 00:45 – Updated: 2023-09-05 22:00
VLAI
Summary
Activerecord-session_store Vulnerable to Timing Attack
Details

The activerecord-session_store (aka Active Record Session Store) component through 1.1.3 for Ruby on Rails does not use a constant-time approach when delivering information about whether a guessed session ID is valid. Consequently, remote attackers can leverage timing discrepancies to achieve a correct guess in a relatively short amount of time. This is a related issue to CVE-2019-16782.

Recommendation

This has been fixed in version 2.0.0. All users are advised to update to this version or later.

Show details on source website

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 1.1.3"
      },
      "package": {
        "ecosystem": "RubyGems",
        "name": "activerecord-session_store"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.0.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2019-25025"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-208"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2021-03-09T00:45:19Z",
    "nvd_published_at": "2021-03-05T06:15:00Z",
    "severity": "MODERATE"
  },
  "details": "The `activerecord-session_store` (aka Active Record Session Store) component through 1.1.3 for Ruby on Rails does not use a constant-time approach when delivering information about whether a guessed session ID is valid. Consequently, remote attackers can leverage timing discrepancies to achieve a correct guess in a relatively short amount of time. This is a related issue to CVE-2019-16782. \n\n## Recommendation\n\nThis has been fixed in version 2.0.0.  All users are advised to update to this version or later.",
  "id": "GHSA-cvw2-xj8r-mjf7",
  "modified": "2023-09-05T22:00:39Z",
  "published": "2021-03-09T00:45:31Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2019-25025"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rails/activerecord-session_store/pull/151"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rails/activerecord-session_store/commit/9d4dd113d3010b82daaadf0b0ee6b9fb2afb2160"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/rails/activerecord-session_store"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rails/activerecord-session_store/releases/tag/v2.0.0"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rubysec/ruby-advisory-db/blob/master/activerecord-session_store/CVE-2019-25025.yml"
    },
    {
      "type": "WEB",
      "url": "https://rubygems.org/gems/activerecord-session_store"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Activerecord-session_store Vulnerable to Timing Attack"
}

GHSA-CX8R-G3C8-JCFG

Vulnerability from github – Published: 2026-08-11 18:30 – Updated: 2026-08-11 18:30
VLAI
Details

Observable Timing Discrepancy in the AMD Vitis Libraries ECDSA secp256k1 component could allow attackers with local access to potentially perform timing analysis or electromagnetic emanation attacks, resulting in high confidentiality and integrity impact due to the exposure of private cryptographic keys.

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2026-43606"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-208"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-11T17:17:58Z",
    "severity": "HIGH"
  },
  "details": "Observable Timing Discrepancy in the AMD Vitis Libraries ECDSA secp256k1 component could allow attackers with local access to potentially perform timing analysis or electromagnetic emanation attacks, resulting in high confidentiality and integrity impact due to the exposure of private cryptographic keys.",
  "id": "GHSA-cx8r-g3c8-jcfg",
  "modified": "2026-08-11T18:30:55Z",
  "published": "2026-08-11T18:30:55Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-43606"
    },
    {
      "type": "WEB",
      "url": "https://www.amd.com/en/resources/product-security/bulletin/AMD-SB-8015.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

GHSA-F34Q-F47H-V25C

Vulnerability from github – Published: 2026-08-13 09:31 – Updated: 2026-08-13 09:31
VLAI
Details

Padding oracle attack vulnerability in Oberon microsystem AG’s Oberon PSA Crypto library in all versions since 1.0.0 and prior to 2.1.1 allows an attacker to recover plaintexts via timing measurements of RSA PKCS#1 v1.5 decrypt operations.

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2026-16459"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-208"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-13T09:17:12Z",
    "severity": "MODERATE"
  },
  "details": "Padding oracle attack vulnerability in Oberon microsystem AG\u2019s Oberon PSA Crypto library in all versions since 1.0.0 and prior to 2.1.1 allows an attacker to recover plaintexts via timing measurements of RSA PKCS#1 v1.5 decrypt operations.",
  "id": "GHSA-f34q-f47h-v25c",
  "modified": "2026-08-13T09:31:10Z",
  "published": "2026-08-13T09:31:10Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-16459"
    },
    {
      "type": "WEB",
      "url": "https://www.oberon.ch/security-advisories/cve-2026-16459"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

GHSA-F9F9-4R63-4QCC

Vulnerability from github – Published: 2022-10-19 19:00 – Updated: 2022-12-16 17:22
VLAI
Summary
Non-constant time webhook token comparison in Jenkins GitLab Plugin
Details

GitLab Plugin 1.5.35 and earlier does not use a constant-time comparison when checking whether the provided and expected webhook token are equal.

This could potentially allow attackers to use statistical methods to obtain a valid webhook token.

GitLab Plugin 1.5.36 uses a constant-time comparison when validating the webhook token.

Show details on source website

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 1.5.35"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "org.jenkins-ci.plugins:gitlab-plugin"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.5.36"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2022-43411"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-203",
      "CWE-208"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2022-10-19T22:22:43Z",
    "nvd_published_at": "2022-10-19T16:15:00Z",
    "severity": "LOW"
  },
  "details": "GitLab Plugin 1.5.35 and earlier does not use a constant-time comparison when checking whether the provided and expected webhook token are equal.\n\nThis could potentially allow attackers to use statistical methods to obtain a valid webhook token.\n\nGitLab Plugin 1.5.36 uses a constant-time comparison when validating the webhook token.",
  "id": "GHSA-f9f9-4r63-4qcc",
  "modified": "2022-12-16T17:22:29Z",
  "published": "2022-10-19T19:00:22Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2022-43411"
    },
    {
      "type": "WEB",
      "url": "https://github.com/jenkinsci/gitlab-plugin/commit/882f84c6a42b42b74ff7c9803d814f61b8fde0ed"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/jenkinsci/gitlab-plugin"
    },
    {
      "type": "WEB",
      "url": "https://www.jenkins.io/security/advisory/2022-10-19/#SECURITY-2877"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2022/10/19/3"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Non-constant time webhook token comparison in Jenkins GitLab Plugin"
}

GHSA-FJ6F-6933-839J

Vulnerability from github – Published: 2022-05-24 17:07 – Updated: 2022-12-19 21:06
VLAI
Summary
Non-constant time HMAC comparison
Details

Jenkins 2.218 and earlier, LTS 2.204.1 and earlier does not use a constant-time comparison when checking whether two HMACs are equal. This could potentially allow attackers to use statistical methods to obtain a valid HMAC for an attacker-controlled input value.

Jenkins 2.219, LTS 2.204.2 now uses a constant-time comparison when validating HMACs.

Show details on source website

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 2.204.1"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "org.jenkins-ci.main:jenkins-core"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.204.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 2.218"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "org.jenkins-ci.main:jenkins-core"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.205"
            },
            {
              "fixed": "2.219"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2020-2102"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-203",
      "CWE-208"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2022-12-19T21:06:59Z",
    "nvd_published_at": "2020-01-29T16:15:00Z",
    "severity": "MODERATE"
  },
  "details": "Jenkins 2.218 and earlier, LTS 2.204.1 and earlier does not use a constant-time comparison when checking whether two HMACs are equal. This could potentially allow attackers to use statistical methods to obtain a valid HMAC for an attacker-controlled input value.\n\nJenkins 2.219, LTS 2.204.2 now uses a constant-time comparison when validating HMACs.",
  "id": "GHSA-fj6f-6933-839j",
  "modified": "2022-12-19T21:06:59Z",
  "published": "2022-05-24T17:07:40Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2020-2102"
    },
    {
      "type": "WEB",
      "url": "https://github.com/jenkinsci/jenkins/commit/6f35dbb939ebe947bdb1979010b208480f1d0e31"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHBA-2020:0402"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHBA-2020:0675"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2020:0681"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2020:0683"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/jenkinsci/jenkins"
    },
    {
      "type": "WEB",
      "url": "https://jenkins.io/security/advisory/2020-01-29/#SECURITY-1660"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2020/01/29/1"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Non-constant time HMAC comparison"
}

GHSA-FP46-6VFW-GC9C

Vulnerability from github – Published: 2026-08-28 22:26 – Updated: 2026-08-28 22:26
VLAI
Summary
free5GC AUSF uses non-constant-time authentication comparisons and logs XRES* in 5G-AKA
Details

Summary

The AUSF component of free5GC compares authentication response values with normal Go equality helpers instead of constant-time cryptographic comparison functions.

Two authentication flows are affected in internal/sbi/processor/ue_authentication.go:

  1. 5G-AKA confirmation compares RES* and XRES* with strings.EqualFold().
  2. EAP-AKA' confirmation compares AT_MAC with bytes.Equal() and compares XRES and RES with ==.

These functions are not designed to be constant-time cryptographic comparators and may return earlier depending on the location of the first mismatch.

Additionally, the 5G-AKA confirmation path logs both the received res* and the expected Xres* at INFO level immediately before comparing them. The XRES* value is authentication material and should not be written to application logs.

The timing side channel was confirmed as a code issue, but practical exploitation over HTTP was not demonstrated in the lab because the comparator-level signal is much smaller than HTTP/SBI noise. The XRES* logging issue is directly observable in AUSF logs.

Confirmed on github.com/free5gc/ausf v1.4.4 and current main as of the May 2026 analysis.

Details

5G-AKA: RES* / XRES*

In Auth5gAkaComfirmRequestProcedure(), the AUSF logs both values and then compares them with strings.EqualFold():

// internal/sbi/processor/ue_authentication.go
logger.Auth5gAkaLog.Infof("res*: %x\nXres*: %x\n",
    updateConfirmationData.ResStar, ausfCurrentContext.XresStar)

if strings.EqualFold(updateConfirmationData.ResStar, ausfCurrentContext.XresStar) {
    ausfCurrentContext.AuthStatus = models.AusfUeAuthenticationAuthResult_SUCCESS
    confirmDataRsp.AuthResult = models.AusfUeAuthenticationAuthResult_SUCCESS
    success = true
    logger.Auth5gAkaLog.Infoln("5G AKA confirmation succeeded")
    // ...
}

For hexadecimal ASCII strings, strings.EqualFold() performs a character comparison that can terminate when a mismatch is found. It is not a constant-time comparison primitive.

The line immediately before the comparison is more directly exploitable: it writes XresStar to INFO logs. Any operator, compromised sidecar, log collector, SIEM user, or local process with access to AUSF logs can read the expected response value for authentication attempts.

EAP-AKA': AT_MAC, XMAC, XRES, and RES

In EapAuthComfirmRequestProcedure(), the AUSF computes the expected MAC and compares it with the received AT_MAC using bytes.Equal():

K_autStr := ausfCurrentContext.K_aut
K_aut, _ := hex.DecodeString(K_autStr)
XMAC := CalculateAtMAC(K_aut, decodeEapAkaPrimePkt.MACInput)
MAC := decodeEapAkaPrimePkt.Attributes[ausf_context.AT_MAC_ATTRIBUTE].Value
XRES := ausfCurrentContext.XRES
RES := hex.EncodeToString(decodeEapAkaPrimePkt.Attributes[ausf_context.AT_RES_ATTRIBUTE].Value)

if !bytes.Equal(MAC, XMAC) {
    eapOK = false
    eapErrStr = "EAP-AKA' integrity check fail"
} else if XRES == RES {
    logger.AuthELog.Infoln("Correct RES value, EAP-AKA' auth succeed")
    // ...
}

bytes.Equal() is not specified as a constant-time cryptographic comparison. The subsequent XRES == RES string comparison is also not constant-time. The correct primitive for comparing authentication tags and secret response values in Go is crypto/subtle.ConstantTimeCompare, after validating and normalizing input length and encoding.

The EAP-AKA' case is harder to exploit remotely than the 5G-AKA case because the XRES == RES comparison is reached only if AT_MAC is valid. Producing a valid AT_MAC requires session-specific K_aut.

Evidence

Static evidence

Static analysis confirmed:

  • strings.EqualFold(updateConfirmationData.ResStar, ausfCurrentContext.XresStar) in the 5G-AKA confirmation path.
  • logger.Auth5gAkaLog.Infof("res*: %x\nXres*: %x\n", ...) immediately before the comparison.
  • bytes.Equal(MAC, XMAC) in the EAP-AKA' confirmation path.
  • XRES == RES in the EAP-AKA' confirmation path.
  • crypto/subtle is absent from the AUSF authentication processor code.

Internal evidence:

hallazgos/finding10-hres-timing/evidencia/20260526-090151-static-analysis/
hallazgos/finding11-eap-mac-timing/evidencia/20260526-094642-static-analysis/

5G-AKA timing and logging evidence

A timing PoC sent 500 iterations per condition over loopback HTTP/SBI:

Condition A: mismatch near the start
Condition B: mismatch in the middle
Condition C: mismatch near the end
Condition D: full match

The comparator-position signal was not distinguishable from HTTP noise:

Delta C-A: approximately -1.5 us
2-sigma noise threshold: approximately 557 us
Result: SIGNAL NOT CLEAR

This is consistent with the expected signal-to-noise ratio: the comparator-level timing difference is in the nanosecond range, while the HTTP/SBI path adds hundreds of microseconds of variance.

The same lab run confirmed that AUSF logs include XresStar in plaintext at INFO level. This does not require statistical inference.

Internal evidence:

hallazgos/finding10-hres-timing/evidencia/20260526-093558-timing-poc/

EAP-AKA' timing evidence

A timing PoC sent 500 iterations per condition against the EAP-AKA' confirmation path:

A: first MAC byte incorrect
B: first 8 MAC bytes correct
C: MAC correct, XRES incorrect
D: MAC correct, XRES correct

Observed medians were all around 464-467 us, and the HTTP-level timing signal was not detectable:

A: 466.6 us
B: 466.5 us
C: 464.2 us
D: 464.2 us
Delta D-A: approximately -2.4 us
2-sigma noise threshold: approximately 716 us
Result: SIGNAL NOT CLEAR

This confirms the expected practical limitation of a remote HTTP timing attack.

Internal evidence:

hallazgos/finding11-eap-mac-timing/evidencia/20260526-103822-timing-poc/

Local CPU benchmark for bytes.Equal()

A direct Go microbenchmark without HTTP overhead measured bytes.Equal() for 16-byte values. The raw benchmark data showed a monotonic increase as more leading bytes matched. The median delta from N=0 matching bytes to N=15 matching bytes was roughly 0.31 ns, or more than 20%.

This confirms that the local comparator is not position-independent at CPU level, even though the signal is too small to exploit remotely over HTTP in normal conditions.

Internal evidence:

hallazgos/finding11-eap-mac-timing/evidencia/20260526-104842-cpu-benchmark/

Uprobe path confirmation

Linux uprobes on the live AUSF process confirmed that requests reach the relevant comparison paths:

  • MAC comparison path is hit for both failing and successful EAP-AKA' attempts.
  • XRES comparison path is hit only when MAC verification passes.

Internal evidence:

hallazgos/finding11-eap-mac-timing/evidencia/20260526-053510-ebpf-uprobe/

Impact

There are two impact classes.

Sensitive value in logs

The 5G-AKA path logs XRES*, the expected response value, at INFO level. In deployments where AUSF logs are collected centrally or are readable by lower-privileged operators, infrastructure agents, compromised containers, or log-processing systems, this exposes authentication material that should remain internal to the authentication procedure.

The exact exploitability depends on whether the attacker can correlate log access with an active authentication context and submit the confirmation before the context is consumed or failed. Regardless, writing XRES* to application logs is an unsafe handling of authentication material.

Timing side channel / cryptographic hardening issue

The non-constant-time comparisons are real code issues and should be fixed, but we did not demonstrate a practical remote timing oracle over HTTP/SBI. The measured comparator signal is too small relative to HTTP noise in the lab.

The risk is higher in environments where an attacker has a lower-noise measurement point, local co-residency, kernel tracing capabilities, or another side channel that can observe the comparison more directly.

Suggested remediation

  1. Remove XRES*, RES*, XRES, RES, K_aut, AT_MAC, and derived authentication material from INFO logs. If logging is necessary, log only metadata such as the authentication context ID, SUPI/SUCI in redacted form, result, and failure class.

  2. Replace strings.EqualFold() and string == comparisons for authentication values with constant-time comparisons.

  3. Normalize encodings before comparison. For hex-encoded values, decode both inputs first, validate expected lengths, and then compare fixed-size byte slices.

Example for 5G-AKA:

resStar, err1 := hex.DecodeString(updateConfirmationData.ResStar)
xresStar, err2 := hex.DecodeString(ausfCurrentContext.XresStar)

if err1 == nil && err2 == nil &&
    len(resStar) == len(xresStar) &&
    subtle.ConstantTimeCompare(resStar, xresStar) == 1 {
    // success
} else {
    // failure
}

Example for EAP-AKA' MAC:

if len(MAC) != len(XMAC) || subtle.ConstantTimeCompare(MAC, XMAC) != 1 {
    eapOK = false
    eapErrStr = "EAP-AKA' integrity check fail"
}

Example for EAP-AKA' XRES:

res, err1 := hex.DecodeString(RES)
xres, err2 := hex.DecodeString(XRES)

if err1 == nil && err2 == nil &&
    len(res) == len(xres) &&
    subtle.ConstantTimeCompare(res, xres) == 1 {
    // success
}
  1. Add unit tests that ensure authentication values are not written to logs.

  2. Consider avoiding a second UDM notification call in the 5G-AKA failure path if the first failure notification already reports the result. In the lab, failure performed two UDM calls while success performed one; this creates a coarse success/failure timing difference, although that result is already visible through the API response.

Prior art / non-duplication note

Known recent free5GC AUSF issues such as CVE-2026-33063 concern different failure modes and code paths. This report concerns cryptographic comparison and logging behavior in internal/sbi/processor/ue_authentication.go.

Show details on source website

{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/free5gc/ausf"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.4.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-55785"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-208",
      "CWE-385",
      "CWE-532"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-08-28T22:26:16Z",
    "nvd_published_at": null,
    "severity": "LOW"
  },
  "details": "### Summary\n\nThe AUSF component of free5GC compares authentication response values with normal Go equality helpers instead of constant-time cryptographic comparison functions.\n\nTwo authentication flows are affected in `internal/sbi/processor/ue_authentication.go`:\n\n1. 5G-AKA confirmation compares `RES*` and `XRES*` with `strings.EqualFold()`.\n2. EAP-AKA\u0027 confirmation compares `AT_MAC` with `bytes.Equal()` and compares `XRES` and `RES` with `==`.\n\nThese functions are not designed to be constant-time cryptographic comparators and may return earlier depending on the location of the first mismatch.\n\nAdditionally, the 5G-AKA confirmation path logs both the received `res*` and the expected `Xres*` at INFO level immediately before comparing them. The `XRES*` value is authentication material and should not be written to application logs.\n\nThe timing side channel was confirmed as a code issue, but practical exploitation over HTTP was not demonstrated in the lab because the comparator-level signal is much smaller than HTTP/SBI noise. The `XRES*` logging issue is directly observable in AUSF logs.\n\nConfirmed on `github.com/free5gc/ausf` v1.4.4 and current main as of the May 2026 analysis.\n\n### Details\n\n#### 5G-AKA: `RES*` / `XRES*`\n\nIn `Auth5gAkaComfirmRequestProcedure()`, the AUSF logs both values and then compares them with `strings.EqualFold()`:\n\n```go\n// internal/sbi/processor/ue_authentication.go\nlogger.Auth5gAkaLog.Infof(\"res*: %x\\nXres*: %x\\n\",\n    updateConfirmationData.ResStar, ausfCurrentContext.XresStar)\n\nif strings.EqualFold(updateConfirmationData.ResStar, ausfCurrentContext.XresStar) {\n    ausfCurrentContext.AuthStatus = models.AusfUeAuthenticationAuthResult_SUCCESS\n    confirmDataRsp.AuthResult = models.AusfUeAuthenticationAuthResult_SUCCESS\n    success = true\n    logger.Auth5gAkaLog.Infoln(\"5G AKA confirmation succeeded\")\n    // ...\n}\n```\n\nFor hexadecimal ASCII strings, `strings.EqualFold()` performs a character comparison that can terminate when a mismatch is found. It is not a constant-time comparison primitive.\n\nThe line immediately before the comparison is more directly exploitable: it writes `XresStar` to INFO logs. Any operator, compromised sidecar, log collector, SIEM user, or local process with access to AUSF logs can read the expected response value for authentication attempts.\n\n#### EAP-AKA\u0027: `AT_MAC`, `XMAC`, `XRES`, and `RES`\n\nIn `EapAuthComfirmRequestProcedure()`, the AUSF computes the expected MAC and compares it with the received `AT_MAC` using `bytes.Equal()`:\n\n```go\nK_autStr := ausfCurrentContext.K_aut\nK_aut, _ := hex.DecodeString(K_autStr)\nXMAC := CalculateAtMAC(K_aut, decodeEapAkaPrimePkt.MACInput)\nMAC := decodeEapAkaPrimePkt.Attributes[ausf_context.AT_MAC_ATTRIBUTE].Value\nXRES := ausfCurrentContext.XRES\nRES := hex.EncodeToString(decodeEapAkaPrimePkt.Attributes[ausf_context.AT_RES_ATTRIBUTE].Value)\n\nif !bytes.Equal(MAC, XMAC) {\n    eapOK = false\n    eapErrStr = \"EAP-AKA\u0027 integrity check fail\"\n} else if XRES == RES {\n    logger.AuthELog.Infoln(\"Correct RES value, EAP-AKA\u0027 auth succeed\")\n    // ...\n}\n```\n\n`bytes.Equal()` is not specified as a constant-time cryptographic comparison. The subsequent `XRES == RES` string comparison is also not constant-time. The correct primitive for comparing authentication tags and secret response values in Go is `crypto/subtle.ConstantTimeCompare`, after validating and normalizing input length and encoding.\n\nThe EAP-AKA\u0027 case is harder to exploit remotely than the 5G-AKA case because the `XRES == RES` comparison is reached only if `AT_MAC` is valid. Producing a valid `AT_MAC` requires session-specific `K_aut`.\n\n### Evidence\n\n#### Static evidence\n\nStatic analysis confirmed:\n\n- `strings.EqualFold(updateConfirmationData.ResStar, ausfCurrentContext.XresStar)` in the 5G-AKA confirmation path.\n- `logger.Auth5gAkaLog.Infof(\"res*: %x\\nXres*: %x\\n\", ...)` immediately before the comparison.\n- `bytes.Equal(MAC, XMAC)` in the EAP-AKA\u0027 confirmation path.\n- `XRES == RES` in the EAP-AKA\u0027 confirmation path.\n- `crypto/subtle` is absent from the AUSF authentication processor code.\n\nInternal evidence:\n\n```text\nhallazgos/finding10-hres-timing/evidencia/20260526-090151-static-analysis/\nhallazgos/finding11-eap-mac-timing/evidencia/20260526-094642-static-analysis/\n```\n\n#### 5G-AKA timing and logging evidence\n\nA timing PoC sent 500 iterations per condition over loopback HTTP/SBI:\n\n```text\nCondition A: mismatch near the start\nCondition B: mismatch in the middle\nCondition C: mismatch near the end\nCondition D: full match\n```\n\nThe comparator-position signal was not distinguishable from HTTP noise:\n\n```text\nDelta C-A: approximately -1.5 us\n2-sigma noise threshold: approximately 557 us\nResult: SIGNAL NOT CLEAR\n```\n\nThis is consistent with the expected signal-to-noise ratio: the comparator-level timing difference is in the nanosecond range, while the HTTP/SBI path adds hundreds of microseconds of variance.\n\nThe same lab run confirmed that AUSF logs include `XresStar` in plaintext at INFO level. This does not require statistical inference.\n\nInternal evidence:\n\n```text\nhallazgos/finding10-hres-timing/evidencia/20260526-093558-timing-poc/\n```\n\n#### EAP-AKA\u0027 timing evidence\n\nA timing PoC sent 500 iterations per condition against the EAP-AKA\u0027 confirmation path:\n\n```text\nA: first MAC byte incorrect\nB: first 8 MAC bytes correct\nC: MAC correct, XRES incorrect\nD: MAC correct, XRES correct\n```\n\nObserved medians were all around 464-467 us, and the HTTP-level timing signal was not detectable:\n\n```text\nA: 466.6 us\nB: 466.5 us\nC: 464.2 us\nD: 464.2 us\nDelta D-A: approximately -2.4 us\n2-sigma noise threshold: approximately 716 us\nResult: SIGNAL NOT CLEAR\n```\n\nThis confirms the expected practical limitation of a remote HTTP timing attack.\n\nInternal evidence:\n\n```text\nhallazgos/finding11-eap-mac-timing/evidencia/20260526-103822-timing-poc/\n```\n\n#### Local CPU benchmark for `bytes.Equal()`\n\nA direct Go microbenchmark without HTTP overhead measured `bytes.Equal()` for 16-byte values. The raw benchmark data showed a monotonic increase as more leading bytes matched. The median delta from `N=0` matching bytes to `N=15` matching bytes was roughly 0.31 ns, or more than 20%.\n\nThis confirms that the local comparator is not position-independent at CPU level, even though the signal is too small to exploit remotely over HTTP in normal conditions.\n\nInternal evidence:\n\n```text\nhallazgos/finding11-eap-mac-timing/evidencia/20260526-104842-cpu-benchmark/\n```\n\n#### Uprobe path confirmation\n\nLinux uprobes on the live AUSF process confirmed that requests reach the relevant comparison paths:\n\n- MAC comparison path is hit for both failing and successful EAP-AKA\u0027 attempts.\n- XRES comparison path is hit only when MAC verification passes.\n\nInternal evidence:\n\n```text\nhallazgos/finding11-eap-mac-timing/evidencia/20260526-053510-ebpf-uprobe/\n```\n\n### Impact\n\nThere are two impact classes.\n\n#### Sensitive value in logs\n\nThe 5G-AKA path logs `XRES*`, the expected response value, at INFO level. In deployments where AUSF logs are collected centrally or are readable by lower-privileged operators, infrastructure agents, compromised containers, or log-processing systems, this exposes authentication material that should remain internal to the authentication procedure.\n\nThe exact exploitability depends on whether the attacker can correlate log access with an active authentication context and submit the confirmation before the context is consumed or failed. Regardless, writing `XRES*` to application logs is an unsafe handling of authentication material.\n\n#### Timing side channel / cryptographic hardening issue\n\nThe non-constant-time comparisons are real code issues and should be fixed, but we did not demonstrate a practical remote timing oracle over HTTP/SBI. The measured comparator signal is too small relative to HTTP noise in the lab.\n\nThe risk is higher in environments where an attacker has a lower-noise measurement point, local co-residency, kernel tracing capabilities, or another side channel that can observe the comparison more directly.\n\n### Suggested remediation\n\n1. Remove `XRES*`, `RES*`, `XRES`, `RES`, `K_aut`, `AT_MAC`, and derived authentication material from INFO logs. If logging is necessary, log only metadata such as the authentication context ID, SUPI/SUCI in redacted form, result, and failure class.\n\n2. Replace `strings.EqualFold()` and string `==` comparisons for authentication values with constant-time comparisons.\n\n3. Normalize encodings before comparison. For hex-encoded values, decode both inputs first, validate expected lengths, and then compare fixed-size byte slices.\n\nExample for 5G-AKA:\n\n```go\nresStar, err1 := hex.DecodeString(updateConfirmationData.ResStar)\nxresStar, err2 := hex.DecodeString(ausfCurrentContext.XresStar)\n\nif err1 == nil \u0026\u0026 err2 == nil \u0026\u0026\n    len(resStar) == len(xresStar) \u0026\u0026\n    subtle.ConstantTimeCompare(resStar, xresStar) == 1 {\n    // success\n} else {\n    // failure\n}\n```\n\nExample for EAP-AKA\u0027 MAC:\n\n```go\nif len(MAC) != len(XMAC) || subtle.ConstantTimeCompare(MAC, XMAC) != 1 {\n    eapOK = false\n    eapErrStr = \"EAP-AKA\u0027 integrity check fail\"\n}\n```\n\nExample for EAP-AKA\u0027 XRES:\n\n```go\nres, err1 := hex.DecodeString(RES)\nxres, err2 := hex.DecodeString(XRES)\n\nif err1 == nil \u0026\u0026 err2 == nil \u0026\u0026\n    len(res) == len(xres) \u0026\u0026\n    subtle.ConstantTimeCompare(res, xres) == 1 {\n    // success\n}\n```\n\n4. Add unit tests that ensure authentication values are not written to logs.\n\n5. Consider avoiding a second UDM notification call in the 5G-AKA failure path if the first failure notification already reports the result. In the lab, failure performed two UDM calls while success performed one; this creates a coarse success/failure timing difference, although that result is already visible through the API response.\n\n### Prior art / non-duplication note\n\nKnown recent free5GC AUSF issues such as CVE-2026-33063 concern different failure modes and code paths. This report concerns cryptographic comparison and logging behavior in `internal/sbi/processor/ue_authentication.go`.",
  "id": "GHSA-fp46-6vfw-gc9c",
  "modified": "2026-08-28T22:26:16Z",
  "published": "2026-08-28T22:26:16Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/free5gc/free5gc/security/advisories/GHSA-fp46-6vfw-gc9c"
    },
    {
      "type": "WEB",
      "url": "https://github.com/free5gc/ausf/commit/7a5a4aa1ec6cd0e1febebf333911c3104968edf0"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/free5gc/free5gc"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "free5GC AUSF uses non-constant-time authentication comparisons and logs XRES* in 5G-AKA"
}

GHSA-FPJ7-9XM6-8HGR

Vulnerability from github – Published: 2022-01-21 23:38 – Updated: 2023-05-24 14:00
VLAI
Summary
Observable Discrepancy and Observable Timing Discrepancy in Jenkins Configuration as Code Plugin
Details

Jenkins Configuration as Code Plugin prior to 1.55.1, 1.54.1, 1.53.1, and 1.47.1 does not use a constant-time comparison when checking whether two authentication tokens are equal.

This could potentially allow attackers to use statistical methods to obtain a valid authentication token.

Configuration as Code Plugin 1.55.1, 1.54.1, 1.53.1, and 1.47.1 now uses a constant-time comparison when validating authentication tokens.

Show details on source website

{
  "affected": [
    {
      "package": {
        "ecosystem": "Maven",
        "name": "io.jenkins:configuration-as-code"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.55"
            },
            {
              "fixed": "1.55.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.55"
      ]
    },
    {
      "package": {
        "ecosystem": "Maven",
        "name": "io.jenkins:configuration-as-code"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.54"
            },
            {
              "fixed": "1.54.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.54"
      ]
    },
    {
      "package": {
        "ecosystem": "Maven",
        "name": "io.jenkins:configuration-as-code"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.48"
            },
            {
              "fixed": "1.53.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Maven",
        "name": "io.jenkins:configuration-as-code"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.47.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2022-23106"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-203",
      "CWE-208"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2022-01-20T14:42:40Z",
    "nvd_published_at": "2022-01-12T20:15:00Z",
    "severity": "LOW"
  },
  "details": "Jenkins Configuration as Code Plugin prior to 1.55.1, 1.54.1, 1.53.1, and 1.47.1 does not use a constant-time comparison when checking whether two authentication tokens are equal.\n\nThis could potentially allow attackers to use statistical methods to obtain a valid authentication token.\n\nConfiguration as Code Plugin 1.55.1, 1.54.1, 1.53.1, and 1.47.1 now uses a constant-time comparison when validating authentication tokens.",
  "id": "GHSA-fpj7-9xm6-8hgr",
  "modified": "2023-05-24T14:00:21Z",
  "published": "2022-01-21T23:38:30Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2022-23106"
    },
    {
      "type": "WEB",
      "url": "https://github.com/jenkinsci/configuration-as-code-plugin/commit/4f425675edf77d382a6fd10890f1a704ff3b2277"
    },
    {
      "type": "WEB",
      "url": "https://github.com/CVEProject/cvelist/blob/00bfb5abeecc9f553a2f42954ee540e493498ee9/2022/23xxx/CVE-2022-23106.json"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/jenkinsci/configuration-as-code-plugin"
    },
    {
      "type": "WEB",
      "url": "https://www.jenkins.io/security/advisory/2022-01-12/#SECURITY-2141"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2022/01/12/6"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Observable Discrepancy and Observable Timing Discrepancy in Jenkins Configuration as Code Plugin"
}

GHSA-FV5R-GP2C-7MWV

Vulnerability from github – Published: 2026-08-11 18:30 – Updated: 2026-08-12 21:31
VLAI
Details

A timing side-channel vulnerability exists in the RSA OAEP decryption implementation. A privileged local attacker with access to the TPM command interface may be able to exploit timing differences to recover information that could allow decryption of ciphertexts encrypted to TPM-managed RSA keys, including the RSA Endorsement Key (EK), including import blobs, credential blobs, and session salts. Under certain conditions, this may also enable the forgery of TPM 2.0 attestations. Refer to TCGVRT0011.

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2026-6727"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-208"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-11T16:17:34Z",
    "severity": "MODERATE"
  },
  "details": "A timing side-channel vulnerability exists in the RSA OAEP decryption implementation. A privileged local attacker with access to the TPM command interface may be able to exploit timing differences to recover information that could allow decryption of ciphertexts encrypted to TPM-managed RSA keys, including the RSA Endorsement Key (EK), including import blobs, credential blobs, and session salts. Under certain conditions, this may also enable the forgery of TPM 2.0 attestations. Refer to TCGVRT0011.",
  "id": "GHSA-fv5r-gp2c-7mwv",
  "modified": "2026-08-12T21:31:28Z",
  "published": "2026-08-11T18:30:48Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-6727"
    },
    {
      "type": "WEB",
      "url": "https://trustedcomputinggroup.org/about/security"
    },
    {
      "type": "WEB",
      "url": "https://trustedcomputinggroup.org/wp-content/uploads/Extended-vrt0010-11-guidance_V1.pdf"
    },
    {
      "type": "WEB",
      "url": "https://trustedcomputinggroup.org/wp-content/uploads/VRT0011-Advisory_Final-1.pdf"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-FW6M-5FQ2-8FQR

Vulnerability from github – Published: 2025-08-29 12:31 – Updated: 2025-08-29 12:31
VLAI
Details

Padding oracle attack vulnerability in Oberon microsystem AG’s ocrypto library in all versions since 3.1.0 and prior to 3.9.2 allows an attacker to recover plaintexts via timing measurements of AES-CBC PKCS#7 decrypt operations.

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2025-7071"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-208"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-08-29T10:15:32Z",
    "severity": "MODERATE"
  },
  "details": "Padding oracle attack vulnerability in Oberon microsystem AG\u2019s ocrypto library in all versions since 3.1.0 and prior to 3.9.2 allows an attacker to recover plaintexts via timing measurements of AES-CBC PKCS#7 decrypt operations.",
  "id": "GHSA-fw6m-5fq2-8fqr",
  "modified": "2025-08-29T12:31:11Z",
  "published": "2025-08-29T12:31:11Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-7071"
    },
    {
      "type": "WEB",
      "url": "https://www.oberon.ch/security-advisories/cve-2025-7071"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

No mitigation information available for this CWE.

CAPEC-462: Cross-Domain Search Timing

An attacker initiates cross domain HTTP / GET requests and times the server responses. The timing of these responses may leak important information on what is happening on the server. Browser's same origin policy prevents the attacker from directly reading the server responses (in the absence of any other weaknesses), but does not prevent the attacker from timing the responses to requests that the attacker issued cross domain.

CAPEC-541: Application Fingerprinting

An adversary engages in fingerprinting activities to determine the type or version of an application installed on a remote target.

CAPEC-580: System Footprinting

An adversary engages in active probing and exploration activities to determine security information about a remote target system. Often times adversaries will rely on remote applications that can be probed for system configurations.