GHSA-Q87J-MXF4-249G
Vulnerability from github – Published: 2026-04-22 15:31 – Updated: 2026-10-15 03:35In the Linux kernel, the following vulnerability has been resolved:
netfilter: ctnetlink: use netlink policy range checks
Replace manual range and mask validations with netlink policy annotations in ctnetlink code paths, so that the netlink core rejects invalid values early and can generate extack errors.
- CTA_PROTOINFO_TCP_STATE: reject values > TCP_CONNTRACK_SYN_SENT2 at policy level, removing the manual >= TCP_CONNTRACK_MAX check.
- CTA_PROTOINFO_TCP_WSCALE_ORIGINAL/REPLY: reject values > TCP_MAX_WSCALE (14). The normal TCP option parsing path already clamps to this value, but the ctnetlink path accepted 0-255, causing undefined behavior when used as a u32 shift count.
- CTA_FILTER_ORIG_FLAGS/REPLY_FLAGS: use NLA_POLICY_MASK with CTA_FILTER_F_ALL, removing the manual mask checks.
- CTA_EXPECT_FLAGS: use NLA_POLICY_MASK with NF_CT_EXPECT_MASK, adding a new mask define grouping all valid expect flags.
Extracted from a broader nf-next patch by Florian Westphal, scoped to ctnetlink for the fixes tree.
{
"affected": [],
"aliases": [
"CVE-2026-31495"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-04-22T14:16:47Z",
"severity": "MODERATE"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: ctnetlink: use netlink policy range checks\n\nReplace manual range and mask validations with netlink policy\nannotations in ctnetlink code paths, so that the netlink core rejects\ninvalid values early and can generate extack errors.\n\n- CTA_PROTOINFO_TCP_STATE: reject values \u003e TCP_CONNTRACK_SYN_SENT2 at\n policy level, removing the manual \u003e= TCP_CONNTRACK_MAX check.\n- CTA_PROTOINFO_TCP_WSCALE_ORIGINAL/REPLY: reject values \u003e TCP_MAX_WSCALE\n (14). The normal TCP option parsing path already clamps to this value,\n but the ctnetlink path accepted 0-255, causing undefined behavior when\n used as a u32 shift count.\n- CTA_FILTER_ORIG_FLAGS/REPLY_FLAGS: use NLA_POLICY_MASK with\n CTA_FILTER_F_ALL, removing the manual mask checks.\n- CTA_EXPECT_FLAGS: use NLA_POLICY_MASK with NF_CT_EXPECT_MASK, adding\n a new mask define grouping all valid expect flags.\n\nExtracted from a broader nf-next patch by Florian Westphal, scoped to\nctnetlink for the fixes tree.",
"id": "GHSA-q87j-mxf4-249g",
"modified": "2026-10-15T03:35:37Z",
"published": "2026-04-22T15:31:43Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-31495"
},
{
"type": "WEB",
"url": "https://cert-portal.siemens.com/productcert/html/ssa-019113.html"
},
{
"type": "WEB",
"url": "https://cert-portal.siemens.com/productcert/html/ssa-082556.html"
},
{
"type": "WEB",
"url": "https://cert-portal.siemens.com/productcert/html/ssa-457936.html"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/2ef71307c86a9f866d6e28f1a0c06e2e9d794474"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/435b576cd2faa75154777868f8cbb73bf71644d3"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/45c33e79ae705b7af97e3117672b6cd258dd0b1b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4f7d25f3f0786402ba48ff7d13b6241d77d975f5"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/675c913b940488a84effdeeac5a1cfb657b59804"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8f15b5071b4548b0aafc03b366eb45c9c6566704"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/c6cb41eaae875501eaaa487b8db6539feb092292"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/fcec5ce2d73a41668b24e3f18c803541602a59f6"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
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