{"schema":"threatline.record/2","record":{"id":"CVE-2026-98260","aliases":[],"summary":"exec: Cleanup POSIX timers right after de_thread()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nexec: Cleanup POSIX timers right after de_thread()\n\nA per-thread CPU timer holds a reference to the PID of the thread it is\nattached to and, while it is armed, its node is queued in that thread's\nposix_cputimers. The task is looked up by that PID.\n\nWhen a non-leader thread exec()s, de_thread() changes which task owns\nthat PID. pid_task(timer->it.cpu.pid, PIDTYPE_PID) then returns NULL,\nbut the node is still queued on tsk, which is alive. timer_lock_sighand()\ntakes a failed lookup to mean that the node is already dequeued, so it\nhas nothing to undo.\n\nbegin_new_exec() calls posix_cpu_timers_exit(me) right after\nexec_task_namespaces() and that removes the leftover node, so the state\nnormally stays invisible. But bprm->point_of_no_return is set before\nde_thread(), so if unshare_files(), set_mm_exe_file(), exec_mmap() or\nexec_task_namespaces() fails, the task dies before it gets there.\nexit_itimers() then frees the k_itimer while its node is still queued,\nand reaping tsk later erases that freed node from the rbtree.\n\nIn short:\n\n      the non-leader thread B           the parent\n\n  timer_create(CLOCK_THREAD_CPUTIME_ID)\n  timer_settime()\n    arm_timer()            // the node is queued on B\n  execve()\n    de_thread(B)\n      exchange_tids(B, leader)  // B's PID now belongs to the leader\n      release_task(leader)\n        __exit_signal(leader)\n          posix_cpu_timers_exit(leader)  // cleans leader's queue, not B's\n          __unhash_process(leader)  // that PID has no task anymore\n    exec_mmap()\n      mmap_read_lock_killable(old_mm)\n                                kill(B, SIGKILL)\n      // -EINTR\n  get_signal()\n    do_exit()\n      exit_itimers()\n        posix_timer_delete()\n          posix_cpu_timer_del()\n        posix_timer_unhash_and_free()  // freed while still queued\n                                wait4()\n                                  release_task(B)\n                                    posix_cpu_timers_exit(B)\n                                      cleanup_timerqueue()\n                                        timerqueue_del()  // use-after-free\n\nMove the POSIX timer cleanup right after de_thread() before any of the\nlater failure conditions brings the task into do_exit().\n\n[ tglx: Move the cleanup right after de_thread() ]","categories":["Operating systems"],"product":"Linux","vendor":"Linux","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98260","source_modified_at":"2026-10-19T09:16:31.364Z","fetched_at":"2026-10-23T18:42:43.628194Z","product":"Linux","vendor":"Linux","versions":[{"version":"55e8c8eb2c7b6bf30e99423ccfe7ca032f498f59","lessThan":"6f1977cea3e85cd8ab55fb337d3e1725fe61d1ce","status":"affected","versionType":"git"},{"version":"55e8c8eb2c7b6bf30e99423ccfe7ca032f498f59","lessThan":"d9ae467e617ca29b825493a362bf0d75ad5f4ac3","status":"affected","versionType":"git"},{"version":"55e8c8eb2c7b6bf30e99423ccfe7ca032f498f59","lessThan":"75aa08b93c65766040f9ca99f41ac85ad22596b6","status":"affected","versionType":"git"},{"version":"55e8c8eb2c7b6bf30e99423ccfe7ca032f498f59","lessThan":"d602877baf36c43c788a5f472c977e0be414029f","status":"affected","versionType":"git"},{"version":"55e8c8eb2c7b6bf30e99423ccfe7ca032f498f59","lessThan":"acb03d3881818581052924a9bbbe92b8741ed448","status":"affected","versionType":"git"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98260","source_modified_at":"2026-10-19T09:16:31.364Z","fetched_at":"2026-10-23T18:42:43.628194Z","product":"Linux","vendor":"Linux","versions":[{"version":"5.7","status":"affected"},{"version":"0","lessThan":"5.7","status":"unaffected","versionType":"semver"},{"version":"6.6.158","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.112","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.54","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.8","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}],"defaultStatus":"affected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98260","source_modified_at":"2026-10-19T09:16:31.364Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"name":"Linux","ecosystem":null},"version":"6f1977cea3e85cd8ab55fb337d3e1725fe61d1ce","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98260","source_modified_at":"2026-10-19T09:16:31.364Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"name":"Linux","ecosystem":null},"version":"75aa08b93c65766040f9ca99f41ac85ad22596b6","basis":"first unaffected version stated in the CVE record"}],"cvss":7.8,"severity":"High","kev":{"listed":false},"epss":{"probability":0.00134,"percentile":0.02647,"score_date":"2026-10-23"},"published_at":"2026-10-06T08:45:24.711Z","modified_at":"2026-10-19T09:16:31.364Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-98260","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-19T09:16:31.364Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-98260","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://git.kernel.org/stable/c/6f1977cea3e85cd8ab55fb337d3e1725fe61d1ce"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/d9ae467e617ca29b825493a362bf0d75ad5f4ac3"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/75aa08b93c65766040f9ca99f41ac85ad22596b6"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/d602877baf36c43c788a5f472c977e0be414029f"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/acb03d3881818581052924a9bbbe92b8741ed448"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","cvss_source":"CVE List","classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"product","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-19T09:16:31.364Z","content_hash":"7ec2006d2476217f70ec4e04d5f1ba799a8e2330f985c81a3f9c46510bef6ac8"}}