Vulnerability-Lookup

GHSA-4VJ2-5MVX-3VCC

Vulnerability from github – Published: 2026-06-18 18:35 – Updated: 2026-06-18 18:35

Details

HAProxy through 3.4.0, fixed in commit 9a6d1fe, contains a null pointer dereference vulnerability in hpack_dht_insert() within src/hpack-tbl.c that fails to validate the return value of hpack_dht_defrag() when the memory pool is exhausted. An attacker can trigger HPACK dynamic table insertions under memory pressure to dereference a NULL pointer and crash HAProxy worker processes, causing denial of service.

Severity

7.5 (High)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

8.7 (High)


                  
                    CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

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{
  "affected": [],
  "aliases": [
    "CVE-2026-55204"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-476"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-18T17:16:34Z",
    "severity": "HIGH"
  },
  "details": "HAProxy through  3.4.0, fixed in commit 9a6d1fe, contains a null pointer dereference vulnerability in hpack_dht_insert() within src/hpack-tbl.c that fails to validate the return value of hpack_dht_defrag() when the memory pool is exhausted. An attacker can trigger HPACK dynamic table insertions under memory pressure to dereference a NULL pointer and crash HAProxy worker processes, causing denial of service.",
  "id": "GHSA-4vj2-5mvx-3vcc",
  "modified": "2026-06-18T18:35:24Z",
  "published": "2026-06-18T18:35:24Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-55204"
    },
    {
      "type": "WEB",
      "url": "https://github.com/haproxy/haproxy/commit/9a6d1fe3f00d86ab4ea6ea6ea0a5d48fc058a513"
    },
    {
      "type": "WEB",
      "url": "https://www.vulncheck.com/advisories/haproxy-null-pointer-dereference-in-hpack-dht-insert-function"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/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"
    }
  ]
}

CVE-2026-55204 (GCVE-0-2026-55204)

Vulnerability from cvelistv5 – Published: 2026-06-18 16:05 – Updated: 2026-06-18 17:26 X_Open Source

Title

HAProxy - NULL Pointer Dereference in hpack_dht_insert Function

Summary

Severity

8.7 (High)


                        
                          CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

7.5 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-476 - NULL Pointer Dereference

Assigner

VulnCheck

References

2 references

URL	Tags
https://github.com/haproxy/haproxy/commit/9a6d1fe…	patch
https://www.vulncheck.com/advisories/haproxy-null…	third-party-advisory

Impacted products

1 product

Vendor	Product	Version
haproxy	haproxy	Affected: 0 , ≤ 3.4.0 (semver) Unaffected: 9a6d1fe3f00d86ab4ea6ea6ea0a5d48fc058a513 (git)

Date Public

2026-06-16 00:00

Credits

Tristan Madani (@TristanInSec)

Show details on NVD website

JSON

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                  },
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                "role": "CISA Coordinator",
                "timestamp": "2026-06-18T17:26:27.738915Z",
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Sightings

Author	Source	Type	Date	Other

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.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-4VJ2-5MVX-3VCC

CVE-2026-55204 (GCVE-0-2026-55204)

Tags

Sightings

Nomenclature