{"id":"CVE-2026-74594","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-74594","generatedAt":"2026-10-28T03:30:47.357Z","title":"In the Linux kernel, the following vulnerability has been resolved: sched/psi: Shut down rtpoll_timer in psi_cgroup_free() psi_schedule_rtpoll_work() is called locklessly from the scheduler hotpath and can race psi_trigger_destroy() taking down the last…","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsched/psi: Shut down rtpoll_timer in psi_cgroup_free()\n\npsi_schedule_rtpoll_work() is called locklessly from the scheduler hotpath\nand can race psi_trigger_destroy() taking down the last rtpoll trigger under\nrtpoll_trigger_lock:\n\n  psi_schedule_rtpoll_work()        psi_trigger_destroy()\n\n  rcu_read_lock();\n  task = rcu_dereference(rtpoll_task);\n                                    rcu_assign_pointer(rtpoll_task, NULL);\n                                    timer_delete(&rtpoll_timer);\n  mod_timer(&rtpoll_timer, ...);\n  rcu_read_unlock();\n                                    synchronize_rcu();\n                                    kthread_stop(task_to_destroy);\n\nThe group can then be freed with the re-armed timer still pending, and\npoll_timer_fn() runs on freed memory.\n\n461daba06bdc (\"psi: eliminate kthread_worker from psi trigger scheduling\nmechanism\") deleted the timer synchronously after the synchronize_rcu(),\nwhich prevented this but raced trigger creation instead: the deletion could\ncancel the timer that a new trigger set armed during the grace period and,\nas creation also reinitialized the timer at the time, corrupt it.\n8f91efd870ea (\"psi: Fix race between psi_trigger_create/destroy\") moved the\ninitialization into group_init() and the deletion into the locked section,\ntrading the creation races for the window above.\n\nNeither placement in the destruction path works. A pending timer firing\nwhile the group is alive is harmless though. poll_timer_fn() just wakes the\nrtpoll waitqueue and doesn't re-arm itself. Bind the timer to the group's\nlifetime instead and shut it down in psi_cgroup_free(). Nothing can arm it\nby then. timer_shutdown_sync() because the timer is never armed again.","published":"2026-08-22T16:16:32.000Z","lastModified":"2026-10-16T20:17:45.000Z","status":"Received","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","cvss":{"version":"3.1","score":7.8,"severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"},"cwe":[],"affected":[],"epss":{"score":0.00129,"percentile":0.02535,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.13%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://git.kernel.org/stable/c/1e5ca82eee59caca6988f9d6e859786aab8a5fa0","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/310b5a537a78c358a4cd244bd767c1a517a05459","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/4addb102154b7cf6e2310ccbe20c3c08619e520d","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/5457025fa8ca3c0d2732109513de839e3e797190","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/611e7821c4f83a671455658797336faecc3a5196","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/8037c5b2b2a447df52542f4d8535895d837bdcbd","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/806fcff98c1d7cb3c1dc0015e55ebdbe819e6b08","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/894a9300d7fb2e2951da92e565ae6de7ddfb0a69","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-74594","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}