GHSA-GM78-P64F-GX97

Vulnerability from github – Published: 2026-04-03 18:31 – Updated: 2026-04-27 15:30
VLAI?
Details

In the Linux kernel, the following vulnerability has been resolved:

netfilter: nf_conntrack_h323: check for zero length in DecodeQ931()

In DecodeQ931(), the UserUserIE code path reads a 16-bit length from the packet, then decrements it by 1 to skip the protocol discriminator byte before passing it to DecodeH323_UserInformation(). If the encoded length is 0, the decrement wraps to -1, which is then passed as a large value to the decoder, leading to an out-of-bounds read.

Add a check to ensure len is positive after the decrement.

Severity ?
9.1 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2026-23455"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-04-03T16:16:32Z",
    "severity": "CRITICAL"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_conntrack_h323: check for zero length in DecodeQ931()\n\nIn DecodeQ931(), the UserUserIE code path reads a 16-bit length from\nthe packet, then decrements it by 1 to skip the protocol discriminator\nbyte before passing it to DecodeH323_UserInformation(). If the encoded\nlength is 0, the decrement wraps to -1, which is then passed as a\nlarge value to the decoder, leading to an out-of-bounds read.\n\nAdd a check to ensure len is positive after the decrement.",
  "id": "GHSA-gm78-p64f-gx97",
  "modified": "2026-04-27T15:30:31Z",
  "published": "2026-04-03T18:31:22Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-23455"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2121f5fbe88daff0f1fc5bc47d359426c74b86b0"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/495e97af9e7249ee02b72bb1d0848a6efc3700f4"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/633e8f87dad32263f6a57dccdb873f042c062111"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/65fa92f79677858b14b9e4b7275f26639afe2710"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9d00fe7d6d7c5b5f1065a6e042b54f2e44bd6df8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b652b05d51003ac074b912684f9ec7486231717b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f173d0f4c0f689173f8cdac79991043a4a89bf66"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f5e4f4e4cdb75ec36802059a94195a31f193da60"
    }
  ],
  "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:H",
      "type": "CVSS_V3"
    }
  ]
}


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