GHSA-3MWM-PXVJ-5V4X

Vulnerability from github – Published: 2026-07-19 18:31 – Updated: 2026-07-20 15:31
VLAI
Details

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

net: tls: prevent chain-after-chain in plain text SG

Sashiko points out that if end = 0 (start != 0) the current code will create a chain link to content type right after the wrap link:

This would create a chain where the wrap link points directly to another chain link. The scatterlist API sg_next iterator does not recursively resolve consecutive chain links.

meaning this is illegal input to crypto.

The wrapping link is unnecessary if end = 0. end is the entry after the last one used so end = 0 means there's nothing pushed after the wrap:

end start i v v v [ ]...[ ][ d ][ d ][ d ][ d ][rsv for wrap]

Skip the wrapping in this case.

TLS 1.3 can use the "wrapping slot" for it's chaining if end = 0. This avoids the chain-after-chain.

Move the wrap chaining before marking END and chaining off content type, that feels like more logical ordering to me, but should not matter from functional perspective.

Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2026-64046"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-19T16:17:44Z",
    "severity": "CRITICAL"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: tls: prevent chain-after-chain in plain text SG\n\nSashiko points out that if end = 0 (start != 0) the current\ncode will create a chain link to content type right after\nthe wrap link:\n\n  This would create a chain where the wrap link points directly\n  to another chain link. The scatterlist API sg_next iterator\n  does not recursively resolve consecutive chain links.\n\nmeaning this is illegal input to crypto.\n\nThe wrapping link is unnecessary if end = 0. end is the entry after\nthe last one used so end = 0 means there\u0027s nothing pushed after\nthe wrap:\n\n   end         start            i\n    v            v              v\n  [   ]...[   ][ d ][ d ][ d ][ d ][rsv for wrap]\n\nSkip the wrapping in this case.\n\nTLS 1.3 can use the \"wrapping slot\" for it\u0027s chaining if end = 0.\nThis avoids the chain-after-chain.\n\nMove the wrap chaining before marking END and chaining off content\ntype, that feels like more logical ordering to me, but should not\nmatter from functional perspective.",
  "id": "GHSA-3mwm-pxvj-5v4x",
  "modified": "2026-07-20T15:31:57Z",
  "published": "2026-07-19T18:31:50Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64046"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/410351158dfef2d67fea6603680b3a6013c6ed9d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/49a5faaa471ddcd37b6893970c9916eb836e7c31"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/91359966e247c0244c66d50bbb8e74aefa4321c3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/929b1548e63ac72e104c07d8ee8cbbeeba2fa89a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/acdc12b71c9aa4be5dcd2c8062753c6d2033e235"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/af855f4c966afafef74faf8390c7b86568c0d46d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b9c015ef1a7bf1e8dc67f21c6381f36deb2c3a36"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ff26a0e8377dec07e4a7230db7675bed1b9a6d03"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}



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