{"id":"CVE-2026-23393","summary":"bridge: cfm: Fix race condition in peer_mep deletion","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nbridge: cfm: Fix race condition in peer_mep deletion\n\nWhen a peer MEP is being deleted, cancel_delayed_work_sync() is called\non ccm_rx_dwork before freeing. However, br_cfm_frame_rx() runs in\nsoftirq context under rcu_read_lock (without RTNL) and can re-schedule\nccm_rx_dwork via ccm_rx_timer_start() between cancel_delayed_work_sync()\nreturning and kfree_rcu() being called.\n\nThe following is a simple race scenario:\n\n           cpu0                                     cpu1\n\nmep_delete_implementation()\n  cancel_delayed_work_sync(ccm_rx_dwork);\n                                           br_cfm_frame_rx()\n                                             // peer_mep still in hlist\n                                             if (peer_mep-\u003eccm_defect)\n                                               ccm_rx_timer_start()\n                                                 queue_delayed_work(ccm_rx_dwork)\n  hlist_del_rcu(&peer_mep-\u003ehead);\n  kfree_rcu(peer_mep, rcu);\n                                           ccm_rx_work_expired()\n                                             // on freed peer_mep\n\nTo prevent this, cancel_delayed_work_sync() is replaced with\ndisable_delayed_work_sync() in both peer MEP deletion paths, so\nthat subsequent queue_delayed_work() calls from br_cfm_frame_rx()\nare silently rejected.\n\nThe cc_peer_disable() helper retains cancel_delayed_work_sync()\nbecause it is also used for the CC enable/disable toggle path where\nthe work must remain re-schedulable.","modified":"2026-04-02T13:12:23.648708Z","published":"2026-03-25T10:33:17.407Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23393.json"},"references":[{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"},{"type":"WEB","url":"https://git.kernel.org/stable/c/1fd81151f65927fd9edb8ecd12ad45527dbbe5ab"},{"type":"WEB","url":"https://git.kernel.org/stable/c/3715a00855316066cdda69d43648336367422127"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d8f35767bacb3c7769d470a41cf161e3f3c07e70"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e89dbd2736a45f0507949af4748cbbf3ff793146"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23393.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-23393"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"dc32cbb3dbd7da38c700d6e0fc6354df24920525"},{"fixed":"e89dbd2736a45f0507949af4748cbbf3ff793146"},{"fixed":"d8f35767bacb3c7769d470a41cf161e3f3c07e70"},{"fixed":"1fd81151f65927fd9edb8ecd12ad45527dbbe5ab"},{"fixed":"3715a00855316066cdda69d43648336367422127"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-23393.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"6.12.78"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.20"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"6.19.10"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-23393.json"}}],"schema_version":"1.7.5"}