{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-74594", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-15T05:44:03.919Z", "datePublished": "2026-08-22T15:31:44.894Z", "dateUpdated": "2026-10-16T19:05:59.691Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-25T05:40:21.246Z" }, "descriptions": [ { "lang": "en", "value": "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." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - Reachable only via local kernel interfaces: writing cgroup *.pressure or /proc/pressure/*, closing the trigger fd, and removing the cgroup; the race involves scheduler hotpath callbacks, not any network protocol.\nAC:L - The attacker controls both race participants—closing/destroying the last privileged PSI trigger while concurrently driving psi_schedule_rtpoll_work() via cgroup task scheduling or the psimon worker—so the mod_timer-after-timer_delete window is reliably winnable.\nPR:L - The vulnerable rtpoll path requires CAP_SYS_RESOURCE (non-2s PSI windows); that capability is available to an unprivileged user who creates a user namespace, and cgroup pressure files are writable under delegated cgroup v2 hierarchies in that namespace.\nUI:N - Exploitation is fully self-driven: the attacker creates the trigger, races its teardown against scheduler activity, and deletes the cgroup; no separate victim action such as mounting a filesystem or opening a file is required.\nS:U - Impact is confined to kernel memory corruption and potential local privilege escalation within the same kernel security authority; it does not cross a VM, container runtime, or IOMMU trust boundary.\nC:H - After psi_cgroup_free() the pending rtpoll_timer fires poll_timer_fn() on a freed psi_group, a classic use-after-free that can expose or corrupt adjacent slab contents and be developed into arbitrary kernel memory read primitives.\nI:H - poll_timer_fn() performs atomic_set() on group->rtpoll_wakeup and wake_up_interruptible() on group->rtpoll_wait after the psi_group is freed, giving attacker-influenced writes into a recycled kmem object suitable for control-flow hijacking.\nA:H - Timer execution on freed psi_group memory can cause immediate kernel oops/panic from invalid pointer dereferences or list corruption, and the race can be retriggered for sustained denial of service on shared cloud/container hosts." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/sched/psi.c" ], "versions": [ { "version": "6bfcb6178925b1fd28c102e53d403091b8f49396", "lessThan": "4addb102154b7cf6e2310ccbe20c3c08619e520d", "status": "affected", "versionType": "git" }, { "version": "8f91efd870ea5d8bc10b0fcc9740db51cd4c0c83", "lessThan": "894a9300d7fb2e2951da92e565ae6de7ddfb0a69", "status": "affected", "versionType": "git" }, { "version": "8f91efd870ea5d8bc10b0fcc9740db51cd4c0c83", "lessThan": "1e5ca82eee59caca6988f9d6e859786aab8a5fa0", "status": "affected", "versionType": "git" }, { "version": "8f91efd870ea5d8bc10b0fcc9740db51cd4c0c83", "lessThan": "310b5a537a78c358a4cd244bd767c1a517a05459", "status": "affected", "versionType": "git" }, { "version": "8f91efd870ea5d8bc10b0fcc9740db51cd4c0c83", "lessThan": "806fcff98c1d7cb3c1dc0015e55ebdbe819e6b08", "status": "affected", "versionType": "git" }, { "version": "8f91efd870ea5d8bc10b0fcc9740db51cd4c0c83", "lessThan": "8037c5b2b2a447df52542f4d8535895d837bdcbd", "status": "affected", "versionType": "git" }, { "version": "8f91efd870ea5d8bc10b0fcc9740db51cd4c0c83", "lessThan": "611e7821c4f83a671455658797336faecc3a5196", "status": "affected", "versionType": "git" }, { "version": "8f91efd870ea5d8bc10b0fcc9740db51cd4c0c83", "lessThan": "5457025fa8ca3c0d2732109513de839e3e797190", "status": "affected", "versionType": "git" }, { "version": "e1e5e263bbe0e6e9c3db36aa48a3c8acf546fa49", "status": "affected", "versionType": "git" }, { "version": "979965c33f734a1666af67900408f997ac669c23", "status": "affected", "versionType": "git" }, { "version": "5.10.50", "lessThan": "5.10.266", "status": "affected", "versionType": "semver" }, { "version": "5.12.17", "lessThan": "5.13", "status": "affected", "versionType": "semver" }, { "version": "5.13.2", "lessThan": "5.14", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/sched/psi.c" ], "versions": [ { "version": "5.14", "status": "affected" }, { "version": "0", "lessThan": "5.14", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.266", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.217", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.183", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.152", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.104", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.45", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.9", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10.50", "versionEndExcluding": "5.10.266" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14", "versionEndExcluding": "5.15.217" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14", "versionEndExcluding": "6.1.183" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14", "versionEndExcluding": "6.6.152" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14", "versionEndExcluding": "6.12.104" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14", "versionEndExcluding": "6.18.45" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14", "versionEndExcluding": "7.1.9" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14", "versionEndExcluding": "7.2" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.12.17" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.13.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/4addb102154b7cf6e2310ccbe20c3c08619e520d" }, { "url": "https://git.kernel.org/stable/c/894a9300d7fb2e2951da92e565ae6de7ddfb0a69" }, { "url": "https://git.kernel.org/stable/c/1e5ca82eee59caca6988f9d6e859786aab8a5fa0" }, { "url": "https://git.kernel.org/stable/c/310b5a537a78c358a4cd244bd767c1a517a05459" }, { "url": "https://git.kernel.org/stable/c/806fcff98c1d7cb3c1dc0015e55ebdbe819e6b08" }, { "url": "https://git.kernel.org/stable/c/8037c5b2b2a447df52542f4d8535895d837bdcbd" }, { "url": "https://git.kernel.org/stable/c/611e7821c4f83a671455658797336faecc3a5196" }, { "url": "https://git.kernel.org/stable/c/5457025fa8ca3c0d2732109513de839e3e797190" } ], "title": "sched/psi: Shut down rtpoll_timer in psi_cgroup_free()", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2026-74594", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "total" } ], "version": "2.0.3", "timestamp": "2026-10-16T19:01:40.497794Z" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-16T19:05:59.691Z" } } ] } }