GHSA-4Q45-QQ5W-X2FJ

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_sip: fix Content-Length u32 truncation in sip_help_tcp()

sip_help_tcp() parses the SIP Content-Length header with simple_strtoul(), which returns unsigned long, but stores the result in unsigned int clen. On 64-bit systems, values exceeding UINT_MAX are silently truncated before computing the SIP message boundary.

For example, Content-Length 4294967328 (2^32 + 32) is truncated to 32, causing the parser to miscalculate where the current message ends. The loop then treats trailing data in the TCP segment as a second SIP message and processes it through the SDP parser.

Fix this by changing clen to unsigned long to match the return type of simple_strtoul(), and reject Content-Length values that exceed the remaining TCP payload length.

Severity ?
8.6 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2026-23457"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-04-03T16:16:32Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_conntrack_sip: fix Content-Length u32 truncation in sip_help_tcp()\n\nsip_help_tcp() parses the SIP Content-Length header with\nsimple_strtoul(), which returns unsigned long, but stores the result in\nunsigned int clen.  On 64-bit systems, values exceeding UINT_MAX are\nsilently truncated before computing the SIP message boundary.\n\nFor example, Content-Length 4294967328 (2^32 + 32) is truncated to 32,\ncausing the parser to miscalculate where the current message ends.  The\nloop then treats trailing data in the TCP segment as a second SIP\nmessage and processes it through the SDP parser.\n\nFix this by changing clen to unsigned long to match the return type of\nsimple_strtoul(), and reject Content-Length values that exceed the\nremaining TCP payload length.",
  "id": "GHSA-4q45-qq5w-x2fj",
  "modified": "2026-04-27T15:30:31Z",
  "published": "2026-04-03T18:31:22Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-23457"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/528b4509c9dfc272e2e92d811915e5211650d383"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/75fcaee5170e7dbbee778927134ef2e9568b4659"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/865dba58958c3a86786f89a501971ab0e3ec6ba9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b75209debb9adab287b3caa982f77788c1e15027"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/cd1b7403ec835f8a0b3f1f7e68ac26af2cb1e42f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d4f17256544cc37f6534a14a27a9dec3540c2015"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ed81b6a7012485acdb9c6c80735a0b7d8e5e1873"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fbce58e719a17aa215c724473fd5baaa4a8dc57c"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H",
      "type": "CVSS_V3"
    }
  ]
}


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