CVE-2026-98260: Software Security Vulnerability Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-pr95-77xq-3v99",
  "modified" : "2026-10-07T09:32:14Z",
  "published" : "2026-10-06T09:31:32Z",
  "aliases" : [ "CVE-2026-98260" ],
  "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() ]",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-98260"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/6f1977cea3e85cd8ab55fb337d3e1725fe61d1ce"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/75aa08b93c65766040f9ca99f41ac85ad22596b6"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/acb03d3881818581052924a9bbbe92b8741ed448"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/d602877baf36c43c788a5f472c977e0be414029f"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/d9ae467e617ca29b825493a362bf0d75ad5f4ac3"
  } ],
  "database_specific" : {
    "cwe_ids" : [ ],
    "severity" : "HIGH",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-10-06T09:18:15Z"
  }
}