{"id":"CVE-2026-74628","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/x25: fix use-after-free of the socket by its timers\n\nThe x25 timers are armed with mod_timer() and cancelled with\ntimer_delete(), so a pending timer holds no refere…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/x25: fix use-after-free of the socket by its timers\n\nThe x25 timers are armed with mod_timer() and cancelled with\ntimer_delete(), so a pending timer holds no refere…","severity":"critical","cvss":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","published":"2026-08-22","updated":"2026-10-14","sourceUpdated":"2026-10-14T13:10:00.187","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-74628","references":[{"url":"https://git.kernel.org/stable/c/1fc9f6d2c7c9fdb341bfe8ca449c990632299ea6","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/2195424c3da2ef1829a63b807e3a900a90e57d85","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/3c4919be5d910db4beebca420953858606fba7d8","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/4bc522b33438fefc3272840ae5988771863a4f1f","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/6b79659590f0f82a9b8efd2ffd55ec6399ebfc33","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ba925a2e98ce967a0e71c5bcbcf5dbd3facaf0c8","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/e92c7e2b41d1528a830bc64c5e4e46dfa8133dda","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/fdd9ac50b9b61ef2b2d52c5156aff788be91454d","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd"],"epss":0.005,"epssPercentile":0.41131,"ingestedAt":"2026-10-14T13:30:58.520Z","slug":"CVE-2026-74628","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnet/x25: fix use-after-free of the socket by its timers\n\nThe x25 timers are armed with mod_timer() and cancelled with\ntimer_delete(), so a pending timer holds no reference on the socket and a\ncancel does not wait for a callback already running on another CPU.\n\nx25_heartbeat_expiry() also rearms unconditionally, so it can reinstall\nsk->sk_timer after __x25_destroy_socket() has passed its cancel point.\nThe following __sock_put() frees the socket while the timer is still\nqueued, and the next expiry uses freed memory.  KASAN reports a\nslab-use-after-free on the kmalloc-2k object freed by close().\n\ntimer_delete_sync() cannot be used here: x25_heartbeat_expiry() and\nx25_timer_expiry() both reach the cancels from inside the timer they\nwould wait on, through __x25_destroy_socket() and x25_disconnect().\n\nArm the timers with sk_reset_timer() and cancel them with sk_stop_timer()\nso that an armed timer owns a reference, and release it in both expiry\nhandlers.  Rearm the heartbeat only while sk_hashed(sk) is still true,\nsince __x25_destroy_socket() unlinks the socket before dropping it.  Arm\nthe deferred destroy timer the same way and drop its reference in\nx25_destroy_timer().\n\nReproduced on net with KASAN, with the heartbeat period shortened so the\nwindow recurs.  With this patch the reproducer no longer triggers a\nreport and /proc/net/x25 drains.\n\nDiscovered by XBOW, triaged by Baul Lee <baul.lee@xbow.com>\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":54,"depthScoreParts":{"impact":53.9,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}