CVE-2026-98260
exec: Cleanup POSIX timers right after de_thread()
No known exploitation. EPSS puts it in the 3rd percentile. Fixed versions are out.
What to do
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- LinuxAffected: ≥ 55e8c8eb2c7b6bf30e99423ccfe7ca032f498f59, < 6f1977cea3e85cd8ab55fb337d3e1725fe61d1ceUpgrade to: 6f1977cea3e85cd8ab55fb337d3e1725fe61d1ceAffected: ≥ 55e8c8eb2c7b6bf30e99423ccfe7ca032f498f59, < d9ae467e617ca29b825493a362bf0d75ad5f4ac3Upgrade to: d9ae467e617ca29b825493a362bf0d75ad5f4ac3Affected: ≥ 55e8c8eb2c7b6bf30e99423ccfe7ca032f498f59, < 75aa08b93c65766040f9ca99f41ac85ad22596b6Upgrade to: 75aa08b93c65766040f9ca99f41ac85ad22596b6Affected: ≥ 55e8c8eb2c7b6bf30e99423ccfe7ca032f498f59, < d602877baf36c43c788a5f472c977e0be414029fUpgrade to: d602877baf36c43c788a5f472c977e0be414029f + 1 more branchStated by: CVE record
Versions as the sources state them. Full version matrix after sign-in
What it is
From the CVE record
In the Linux kernel, the following vulnerability has been resolved: exec: Cleanup POSIX timers right after de_thread() A per-thread CPU timer holds a reference to the PID of the thread it is attached to and, while it is armed, its node is queued in that thread's posix_cputimers. The task is looked up by that PID. When a non-leader thread exec()s, de_thread() changes which task owns that PID. pid_task(timer->it.cpu.pid, PIDTYPE_PID) then returns NULL, but the node is still queued on tsk, which is alive. timer_lock_sighand() takes a failed lookup to mean that the node is already dequeued, so it has nothing to undo. begin_new_exec() calls posix_cpu_timers_exit(me) right after exec_task_namespaces() and that removes the leftover node, so the state normally stays invisible. But bprm->point_of_no_return is set before de_thread(), so if unshare_files(), set_mm_exe_file(), exec_mmap() or exec_task_namespaces() fails, the task dies before it gets there. exit_itimers() then frees the k_itimer while its node is still queued, and reaping tsk later erases that freed node from the rbtree. In short: the non-leader thread B the parent timer_create(CLOCK_THREAD_CPUTIME_ID) timer_settime() arm_timer() // the node is queued on B execve() de_thread(B) exchange_tids(B, leader) // B's PID now belongs to the leader release_task(leader) __exit_signal(leader) posix_cpu_timers_exit(leader) // cleans leader's queue, not B's __unhash_process(leader) // that PID has no task anymore exec_mmap() mmap_read_lock_killable(old_mm) kill(B, SIGKILL) // -EINTR get_signal() do_exit() exit_itimers() posix_timer_delete() posix_cpu_timer_del() posix_timer_unhash_and_free() // freed while still queued wait4() release_task(B) posix_cpu_timers_exit(B) cleanup_timerqueue() timerqueue_del() // use-after-free Move the POSIX timer cleanup right after de_thread() before any of the later failure conditions brings the task into do_exit(). [ tglx: Move the cleanup right after de_thread() ]
In plain language
No plain-language summary for this CVE yet.
Exploitation
Where each signal puts this CVE on the scale from published to confirmed exploited.
- CISA KEV
Not in the catalog. CISA has not confirmed exploitation.
- Public exploits
No public exploit or proof of concept found in the sources we track.
- EPSS
0.1% chance of exploitation activity in the next 30 days, which ranks it in the 3rd percentile of scored CVEs.
Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.
Lifecycle
3 events over 1 day, from the signal feeds we watch.
- Record updated
- Publishedrecord updated
Affected products
Technical detail
CVSS 3.1 vector
Open in the CVSS calculatorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Scored 7.8 by NVD.
How it is reached
- Attack Vector LocalRequires local access to the vulnerable system (e.g. local login, malicious file)
- Attack Complexity LowNo special conditions — the attack can be reliably reproduced
- Privileges Required LowRequires basic user-level privileges
- User Interaction NoneNo user interaction needed — fully automated exploitation
Scope
- Scope UnchangedImpact is limited to the vulnerable component itself
Impact if exploited
- Confidentiality HighTotal information disclosure — all data in the component is compromised
- Integrity HighTotal loss of integrity — attacker can modify any data in the component
- Availability HighTotal denial of service — the component is completely unavailable
Sources
References in the record
- git.kernel.org/stable/c/6f1977cea3e85cd8ab55fb337d3e1725fe61d1ce
- git.kernel.org/stable/c/75aa08b93c65766040f9ca99f41ac85ad22596b6
- git.kernel.org/stable/c/acb03d3881818581052924a9bbbe92b8741ed448
And 2 more references. See all after sign-in
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