CVE-2026-43383 (GCVE-0-2026-43383)

Vulnerability from cvelistv5 – Published: 2026-05-08 14:21 – Updated: 2026-05-08 14:21
VLAI?
Title
net/tcp-md5: Fix MAC comparison to be constant-time
Summary
In the Linux kernel, the following vulnerability has been resolved: net/tcp-md5: Fix MAC comparison to be constant-time To prevent timing attacks, MACs need to be compared in constant time. Use the appropriate helper function for this.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: cfb6eeb4c860592edd123fdea908d23c6ad1c7dc , < 821c8751fdeecdeecabeb11704dd33439c9e4bbc (git)
Affected: cfb6eeb4c860592edd123fdea908d23c6ad1c7dc , < 345a9530756528d7ca407663d659c3c40e75c3dd (git)
Affected: cfb6eeb4c860592edd123fdea908d23c6ad1c7dc , < 5d305a95130a8d08b9545e47f1e18d29d59866cb (git)
Affected: cfb6eeb4c860592edd123fdea908d23c6ad1c7dc , < 02669e2a4d207068edce7e8b5fafd85822018ce6 (git)
Affected: cfb6eeb4c860592edd123fdea908d23c6ad1c7dc , < ae3831b44f477de048287493e184fc3ff913b624 (git)
Affected: cfb6eeb4c860592edd123fdea908d23c6ad1c7dc , < b502e97e29d791ff7a8051f29a414535739be218 (git)
Affected: cfb6eeb4c860592edd123fdea908d23c6ad1c7dc , < 46d0d6f50dab706637f4c18a470aac20a21900d3 (git)
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    Linux Linux Affected: 2.6.20
Unaffected: 0 , < 2.6.20 (semver)
Unaffected: 5.10.253 , ≤ 5.10.* (semver)
Unaffected: 6.1.167 , ≤ 6.1.* (semver)
Unaffected: 6.6.130 , ≤ 6.6.* (semver)
Unaffected: 6.12.78 , ≤ 6.12.* (semver)
Unaffected: 6.18.19 , ≤ 6.18.* (semver)
Unaffected: 6.19.9 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
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{
  "containers": {
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        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/ipv4/Kconfig",
            "net/ipv4/tcp.c",
            "net/ipv4/tcp_ipv4.c",
            "net/ipv6/tcp_ipv6.c"
          ],
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          ],
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          "vendor": "Linux",
          "versions": [
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              "status": "affected",
              "version": "2.6.20"
            },
            {
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.253",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.167",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.130",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.78",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.19",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
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              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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              "operator": "OR"
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        }
      ],
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/tcp-md5: Fix MAC comparison to be constant-time\n\nTo prevent timing attacks, MACs need to be compared in constant\ntime.  Use the appropriate helper function for this."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-08T14:21:30.704Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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          "url": "https://git.kernel.org/stable/c/821c8751fdeecdeecabeb11704dd33439c9e4bbc"
        },
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          "url": "https://git.kernel.org/stable/c/345a9530756528d7ca407663d659c3c40e75c3dd"
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          "url": "https://git.kernel.org/stable/c/46d0d6f50dab706637f4c18a470aac20a21900d3"
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      "title": "net/tcp-md5: Fix MAC comparison to be constant-time",
      "x_generator": {
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  "cveMetadata": {
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-43383",
    "datePublished": "2026-05-08T14:21:30.704Z",
    "dateReserved": "2026-05-01T14:12:56.006Z",
    "dateUpdated": "2026-05-08T14:21:30.704Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
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  }
}


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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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