CVE Tools

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.

Published Updated Sources: CVE.org, NVD

What to do

Find your product and version, then upgrade to the build on the right.

  • 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.

EPSS3rd
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.

  1. Record updated
  2. Publishedrecord updated

Affected products

Technical detail

CVSS: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

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