GHSA-M86Q-CGJ9-94C8

Vulnerability from github – Published: 2026-06-24 18:32 – Updated: 2026-08-03 15:32
VLAI
Details

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

tipc: fix double-free in tipc_buf_append()

tipc_msg_validate() can potentially reallocate the skb it is validating, freeing the old one. In tipc_buf_append(), it was being called with a pointer to a local variable which was a copy of the caller's skb pointer.

If the skb was reallocated and validation subsequently failed, the error handling path would free the original skb pointer, which had already been freed, leading to double-free.

Fix this by checking if head now points to a newly allocated reassembled skb. If it does, reassign *headbuf for later freeing operations.

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-2026-52993"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-415",
      "CWE-763"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-24T17:17:10Z",
    "severity": "CRITICAL"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ntipc: fix double-free in tipc_buf_append()\n\ntipc_msg_validate() can potentially reallocate the skb it is validating,\nfreeing the old one.  In tipc_buf_append(), it was being called with a\npointer to a local variable which was a copy of the caller\u0027s skb\npointer.\n\nIf the skb was reallocated and validation subsequently failed, the error\nhandling path would free the original skb pointer, which had already\nbeen freed, leading to double-free.\n\nFix this by checking if head now points to a newly allocated reassembled\nskb.  If it does, reassign *headbuf for later freeing operations.",
  "id": "GHSA-m86q-cgj9-94c8",
  "modified": "2026-08-03T15:32:38Z",
  "published": "2026-06-24T18:32:43Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-52993"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:45115"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:45116"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:47017"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:49212"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/security/cve/CVE-2026-52993"
    },
    {
      "type": "WEB",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2492437"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0274f24485fc38032d4093e463dc3ff5c7a667c9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1d5e589055880fae229e229e1929e087dbe08cf3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/29940fff14110ca48c5ccc168d121665b51bb778"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4d104882bc815d4ec666ace9155f5f52715879a6"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4ee4deadaae7cb2e3d53af0fc889cf92a73413c0"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a438975a6dcdbd70865978c021650d1485586f0b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d293ca716e7d5dffdaecaf6b9b2f857a33dc3d3a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d3556656c6daebf8def751c7e71d11dd0a180d24"
    },
    {
      "type": "WEB",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52993.json"
    }
  ],
  "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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