{"id":"CVE-2026-74255","summary":"tipc: fix UAF in tipc_l2_send_msg()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ntipc: fix UAF in tipc_l2_send_msg()\n\nSyzbot reported a slab-use-after-free in ipvlan_hard_header() when\ncalled from tipc_l2_send_msg().\n\nThe root cause is that tipc_disable_l2_media() calls synchronize_net()\nwhile b-\u003emedia_ptr is still valid. This allows concurrent RCU readers\nto obtain the device pointer after synchronize_net() has finished.\nThe pointer is cleared later in bearer_disable(), but without any\nsubsequent synchronization, allowing the device to be freed while\nstill in use by readers.\n\nFix this by clearing b-\u003emedia_ptr in tipc_disable_l2_media() before\ncalling synchronize_net().\n\nThis is safe to do now because the call order in bearer_disable()\nwas reversed in 0d051bf93c06 (\"tipc: make bearer packet filtering generic\")\nto call tipc_node_delete_links() (which needs the pointer) before\ndisable_media().\n\nhttps: //lore.kernel.org/netdev/6a2c1007.428ffe26.258b27.015d.GAE@google.com/T/#u","modified":"2026-08-18T03:56:45.091645785Z","published":"2026-08-15T05:57:34.293Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74255.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/0d8a12d7143126afdf9fbe2e3d438650dd6603ed"},{"type":"WEB","url":"https://git.kernel.org/stable/c/35e0297a93c3c34a3924eeef816c03504e3ab5c5"},{"type":"WEB","url":"https://git.kernel.org/stable/c/50ff092633b06382e5091dd5b093ce943d4ac2f9"},{"type":"WEB","url":"https://git.kernel.org/stable/c/609ced2301be1df7e7ed2ef47d1d916674e6ba3b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/71aafa16d79b107b33837f60b6cbc7d0cb8c5708"},{"type":"WEB","url":"https://git.kernel.org/stable/c/aef12b5ce793dea6b3a97a58fd0f946000ae8945"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f4002f1c669cc02e3763f479fc25ff1dfa9e2420"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f4c3d89fc986b0da196ddfc6cfe0ea5d5d08bec6"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74255.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74255"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.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"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"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"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-74255.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"}]}