{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2022-50095", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-06-18T10:57:27.411Z", "datePublished": "2025-06-18T11:02:33.221Z", "dateUpdated": "2026-08-05T08:57:22.791Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T08:57:22.791Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nposix-cpu-timers: Cleanup CPU timers before freeing them during exec\n\nCommit 55e8c8eb2c7b (\"posix-cpu-timers: Store a reference to a pid not a\ntask\") started looking up tasks by PID when deleting a CPU timer.\n\nWhen a non-leader thread calls execve, it will switch PIDs with the leader\nprocess. Then, as it calls exit_itimers, posix_cpu_timer_del cannot find\nthe task because the timer still points out to the old PID.\n\nThat means that armed timers won't be disarmed, that is, they won't be\nremoved from the timerqueue_list. exit_itimers will still release their\nmemory, and when that list is later processed, it leads to a\nuse-after-free.\n\nClean up the timers from the de-threaded task before freeing them. This\nprevents a reported use-after-free." } ], "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 - Exploitation requires local syscalls (clone/pthread_create, timer_create/timer_settime with CLOCK_THREAD_CPUTIME_ID, and execve from a non-leader thread); there is no network or adjacent-vector path into this code.\nAC:L - The bug is a deterministic logic error on the non-leader exec path after PID exchange, not a race against conditions the attacker cannot control; the attacker reliably creates, arms, and triggers the dangling timerqueue entry.\nPR:L - An unprivileged local user can create threads, create and arm self-targeted POSIX CPU timers, and call execve; no capabilities or init-namespace root are required.\nUI:N - The attacker performs all steps themselves; no separate victim action is needed to reach or trigger the use-after-free.\nS:U - Impact is confined to the local kernel/OS authority (standard kernel memory corruption / privilege escalation); it does not cross a VM, IOMMU, or other security boundary.\nC:H - The freed k_itimer remains linked in the per-thread CPU timerqueue and is later processed by run_posix_cpu_timers, yielding a kernel UAF that can be leveraged for arbitrary memory disclosure.\nI:H - The same UAF of a slab-allocated k_itimer enables heap reuse and write/control-flow primitives consistent with kernel timer-object corruption.\nA:H - Processing the dangling timerqueue entry after free causes kernel oops/panic or otherwise crashes the system even when not fully exploited for code execution." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/exec.c" ], "versions": [ { "version": "55e8c8eb2c7b6bf30e99423ccfe7ca032f498f59", "lessThan": "541840859ace9c2ccebc32fa9e376c7bd3def490", "status": "affected", "versionType": "git" }, { "version": "55e8c8eb2c7b6bf30e99423ccfe7ca032f498f59", "lessThan": "9e255ed238fc67058df87b0388ad6d4b2ef3a2bd", "status": "affected", "versionType": "git" }, { "version": "55e8c8eb2c7b6bf30e99423ccfe7ca032f498f59", "lessThan": "e8cb6e8fd9890780f1bfcf5592889e1b879e779c", "status": "affected", "versionType": "git" }, { "version": "55e8c8eb2c7b6bf30e99423ccfe7ca032f498f59", "lessThan": "b2fc1723eb65abb83e00d5f011de670296af0b28", "status": "affected", "versionType": "git" }, { "version": "55e8c8eb2c7b6bf30e99423ccfe7ca032f498f59", "lessThan": "e362359ace6f87c201531872486ff295df306d13", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/exec.c" ], "versions": [ { "version": "5.7", "status": "affected" }, { "version": "0", "lessThan": "5.7", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.137", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.61", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.18.18", "lessThanOrEqual": "5.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.19.2", "lessThanOrEqual": "5.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.0", "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": "5.7", "versionEndExcluding": "5.10.137" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "5.15.61" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "5.18.18" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "5.19.2" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.0" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/541840859ace9c2ccebc32fa9e376c7bd3def490" }, { "url": "https://git.kernel.org/stable/c/9e255ed238fc67058df87b0388ad6d4b2ef3a2bd" }, { "url": "https://git.kernel.org/stable/c/e8cb6e8fd9890780f1bfcf5592889e1b879e779c" }, { "url": "https://git.kernel.org/stable/c/b2fc1723eb65abb83e00d5f011de670296af0b28" }, { "url": "https://git.kernel.org/stable/c/e362359ace6f87c201531872486ff295df306d13" } ], "title": "posix-cpu-timers: Cleanup CPU timers before freeing them during exec", "x_generator": { "engine": "bippy-1.2.0" } } } }