GHSA-RHCJ-6WXJ-R34P

Vulnerability from github – Published: 2026-05-06 12:30 – Updated: 2026-09-14 12:31
VLAI
Details

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

tcp: fix potential race in tcp_v6_syn_recv_sock()

Code in tcp_v6_syn_recv_sock() after the call to tcp_v4_syn_recv_sock() is done too late.

After tcp_v4_syn_recv_sock(), the child socket is already visible from TCP ehash table and other cpus might use it.

Since newinet->pinet6 is still pointing to the listener ipv6_pinfo bad things can happen as syzbot found.

Move the problematic code in tcp_v6_mapped_child_init() and call this new helper from tcp_v4_syn_recv_sock() before the ehash insertion.

This allows the removal of one tcp_sync_mss(), since tcp_v4_syn_recv_sock() will call it with the correct context.

Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Show details on source website
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{
  "affected": [],
  "aliases": [
    "CVE-2026-43198"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-362",
      "CWE-821"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-05-06T12:16:38Z",
    "severity": "CRITICAL"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ntcp: fix potential race in tcp_v6_syn_recv_sock()\n\nCode in tcp_v6_syn_recv_sock() after the call to tcp_v4_syn_recv_sock()\nis done too late.\n\nAfter tcp_v4_syn_recv_sock(), the child socket is already visible\nfrom TCP ehash table and other cpus might use it.\n\nSince newinet-\u003epinet6 is still pointing to the listener ipv6_pinfo\nbad things can happen as syzbot found.\n\nMove the problematic code in tcp_v6_mapped_child_init()\nand call this new helper from tcp_v4_syn_recv_sock() before\nthe ehash insertion.\n\nThis allows the removal of one tcp_sync_mss(), since\ntcp_v4_syn_recv_sock() will call it with the correct\ncontext.",
  "id": "GHSA-rhcj-6wxj-r34p",
  "modified": "2026-09-14T12:31:29Z",
  "published": "2026-05-06T12:30:32Z",
  "references": [
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      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-43198"
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  ],
  "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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