Skip to content
Heist/ feed
Back to feed
CriticalFix available

tipc: fix UAF in tipc_l2_send_msg()

Type: advisorySources: OSV

In the Linux kernel, the following vulnerability has been resolved: tipc: fix UAF in tipc_l2_send_msg() Syzbot reported a slab-use-after-free in ipvlan_hard_header() when called from tipc_l2_send_msg(). The root cause is that tipc_disable_l2_media() calls synchronize_net() while b->media_ptr is still valid. This allows concurrent RCU readers to obtain the device pointer after synchronize_net() has finished. The pointer is cleared later in bearer_disable(), but without any subsequent synchronization, allowing the device to be freed while still in use by readers. Fix this by clearing b->media_ptr in tipc_disable_l2_media() before calling synchronize_net(). This is safe to do now because the call order in bearer_disable() was reversed in 0d051bf93c06 ("tipc: make bearer packet filtering generic") to call tipc_node_delete_links() (which needs the pointer) before disable_media(). https: //lore.kernel.org/netdev/6a2c1007.428ffe26.258b27.015d.GAE@google.com/T/#u

Products
Kernel
Affected versions
Not specified
Fixed versions
5.10.261, 5.15.212, 6.1.178, 6.12.97, 6.18.40, 6.6.145, 7.1.5
CVEs
CVE-2026-74255
Confirmed fixed CVEs
Not specified
Updated in this feed
3 Nov 2026, 23:40 UTC · Revision 1

Source evidence

tipc: fix UAF in tipc_l2_send_msg()

core-osv · Original source

Published 15 Aug 2026, 05:57 UTC

In the Linux kernel, the following vulnerability has been resolved: tipc: fix UAF in tipc_l2_send_msg() Syzbot reported a slab-use-after-free in ipvlan_hard_header() when called from tipc_l2_send_msg(). The root cause is that tipc_disable_l2_media() calls synchronize_net() while b->media_ptr is still valid. This allows concurrent RCU readers to obtain the device pointer after synchronize_net() has finished. The pointer is cleared later in bearer_disable(), but without any subsequent synchronization, allowing the device to be freed while still in use by readers. Fix this by clearing b->media_ptr in tipc_disable_l2_media() before calling synchronize_net(). This is safe to do now because the call order in bearer_disable() was reversed in 0d051bf93c06 ("tipc: make bearer packet filtering generic") to call tipc_node_delete_links() (which needs the pointer) before disable_media(). https: //lore.kernel.org/netdev/6a2c1007.428ffe26.258b27.015d.GAE@google.com/T/#u

osv:CVE-2026-74255

Kernel

Fixed versions: 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.97, 6.18.40, 7.1.5

Complete source record
{
  "id": "f3dfa18d1bb07845aa258fc497fb748327a4dc2b6af5cbf88350b94957fd970a",
  "url": "https://osv.dev/vulnerability/CVE-2026-74255",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "tipc: fix UAF in tipc_l2_send_msg()",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: tipc: fix UAF in tipc_l2_send_msg() Syzbot reported a slab-use-after-free in ipvlan_hard_header() when called from tipc_l2_send_msg(). The root cause is that tipc_disable_l2_media() calls synchronize_net() while b->media_ptr is still valid. This allows concurrent RCU readers to obtain the device pointer after synchronize_net() has finished. The pointer is cleared later in bearer_disable(), but without any subsequent synchronization, allowing the device to be freed while still in use by readers. Fix this by clearing b->media_ptr in tipc_disable_l2_media() before calling synchronize_net(). This is safe to do now because the call order in bearer_disable() was reversed in 0d051bf93c06 (\"tipc: make bearer packet filtering generic\") to call tipc_node_delete_links() (which needs the pointer) before disable_media(). https: //lore.kernel.org/netdev/6a2c1007.428ffe26.258b27.015d.GAE@google.com/T/#u",
    "evidence": "osv:CVE-2026-74255",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.10.261",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.15.212",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.178",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.145",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.97",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.40",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.1.5",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "critical",
    "structured": {
      "id": "CVE-2026-74255",
      "aliases": [
        "CVE-2026-74255"
      ],
      "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": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "282b3a056225b35024246f63feb91d769d714dad"
                },
                {
                  "fixed": "609ced2301be1df7e7ed2ef47d1d916674e6ba3b"
                },
                {
                  "fixed": "71aafa16d79b107b33837f60b6cbc7d0cb8c5708"
                },
                {
                  "fixed": "f4002f1c669cc02e3763f479fc25ff1dfa9e2420"
                },
                {
                  "fixed": "50ff092633b06382e5091dd5b093ce943d4ac2f9"
                },
                {
                  "fixed": "aef12b5ce793dea6b3a97a58fd0f946000ae8945"
                },
                {
                  "fixed": "0d8a12d7143126afdf9fbe2e3d438650dd6603ed"
                },
                {
                  "fixed": "35e0297a93c3c34a3924eeef816c03504e3ab5c5"
                },
                {
                  "fixed": "f4c3d89fc986b0da196ddfc6cfe0ea5d5d08bec6"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-74255.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "4.4.0"
                },
                {
                  "fixed": "5.10.261"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.11.0"
                },
                {
                  "fixed": "5.15.212"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.16.0"
                },
                {
                  "fixed": "6.1.178"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.2.0"
                },
                {
                  "fixed": "6.6.145"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.7.0"
                },
                {
                  "fixed": "6.12.97"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.18.40"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "7.1.5"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-74255.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:32.211618151Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/0d8a12d7143126afdf9fbe2e3d438650dd6603ed",
        "https://git.kernel.org/stable/c/35e0297a93c3c34a3924eeef816c03504e3ab5c5",
        "https://git.kernel.org/stable/c/50ff092633b06382e5091dd5b093ce943d4ac2f9",
        "https://git.kernel.org/stable/c/609ced2301be1df7e7ed2ef47d1d916674e6ba3b",
        "https://git.kernel.org/stable/c/71aafa16d79b107b33837f60b6cbc7d0cb8c5708",
        "https://git.kernel.org/stable/c/aef12b5ce793dea6b3a97a58fd0f946000ae8945",
        "https://git.kernel.org/stable/c/f4002f1c669cc02e3763f479fc25ff1dfa9e2420",
        "https://git.kernel.org/stable/c/f4c3d89fc986b0da196ddfc6cfe0ea5d5d08bec6",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74255.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-74255",
        "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/2026/74xxx/CVE-2026-74255.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-74255",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 499272,
  "published_at": "2026-08-15T05:57:34.293+00:00"
}