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CriticalFix available

tipc: fix double-free in tipc_buf_append()

Type: advisorySources: OSV

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.

Products
Kernel
Affected versions
Not specified
Fixed versions
5.10.258, 5.15.209, 6.1.175, 6.12.91, 6.18.33, 6.6.141, 7.0.10
CVEs
CVE-2026-52993
Confirmed fixed CVEs
Not specified
Updated in this feed
4 Nov 2026, 03:52 UTC · Revision 1

Source evidence

tipc: fix double-free in tipc_buf_append()

core-osv · Original source

Published 24 Jun 2026, 16:29 UTC

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.

osv:CVE-2026-52993

Kernel

Fixed versions: 5.10.258, 5.15.209, 6.1.175, 6.6.141, 6.12.91, 6.18.33, 7.0.10

Complete source record
{
  "id": "f073ac59bbdea7f4169fe34a359137b719017c01a1bb66fe6ffaf2967ec11297",
  "url": "https://osv.dev/vulnerability/CVE-2026-52993",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "tipc: fix double-free in tipc_buf_append()",
    "summary": "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.",
    "evidence": "osv:CVE-2026-52993",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.10.258",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.15.209",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.175",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.141",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.91",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.33",
            "evidence": "/affected/1/ranges"
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          {
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            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "critical",
    "structured": {
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      "aliases": [
        "A-500022799",
        "ASB-A-500022799",
        "CVE-2026-52993"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
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                },
                {
                  "fixed": "d3556656c6daebf8def751c7e71d11dd0a180d24"
                },
                {
                  "fixed": "0274f24485fc38032d4093e463dc3ff5c7a667c9"
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                {
                  "fixed": "4d104882bc815d4ec666ace9155f5f52715879a6"
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                {
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          "database_specific": {
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        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
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                  "introduced": "4.15.0"
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            },
            {
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                {
                  "introduced": "5.11.0"
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                {
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            },
            {
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                {
                  "introduced": "5.16.0"
                },
                {
                  "fixed": "6.1.175"
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              ]
            },
            {
              "type": "ECOSYSTEM",
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                {
                  "introduced": "6.2.0"
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            },
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          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
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          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-52993.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:32.856182155Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/0274f24485fc38032d4093e463dc3ff5c7a667c9",
        "https://git.kernel.org/stable/c/1d5e589055880fae229e229e1929e087dbe08cf3",
        "https://git.kernel.org/stable/c/29940fff14110ca48c5ccc168d121665b51bb778",
        "https://git.kernel.org/stable/c/4d104882bc815d4ec666ace9155f5f52715879a6",
        "https://git.kernel.org/stable/c/4ee4deadaae7cb2e3d53af0fc889cf92a73413c0",
        "https://git.kernel.org/stable/c/a438975a6dcdbd70865978c021650d1485586f0b",
        "https://git.kernel.org/stable/c/d293ca716e7d5dffdaecaf6b9b2f857a33dc3d3a",
        "https://git.kernel.org/stable/c/d3556656c6daebf8def751c7e71d11dd0a180d24",
        "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52993.json",
        "https://access.redhat.com/errata/RHSA-2026:45115",
        "https://access.redhat.com/errata/RHSA-2026:45116",
        "https://access.redhat.com/errata/RHSA-2026:47017",
        "https://access.redhat.com/errata/RHSA-2026:49212",
        "https://access.redhat.com/security/cve/CVE-2026-52993",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/52xxx/CVE-2026-52993.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-52993",
        "https://bugzilla.redhat.com/show_bug.cgi?id=2492437",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/52xxx/CVE-2026-52993.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-52993",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 500145,
  "published_at": "2026-06-24T16:29:06.475+00:00"
}