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CVE Record

CVE-2022-50095: posix-cpu-timers: Cleanup CPU timers before freeing them during exec

In the Linux kernel, the following vulnerability has been resolved: posix-cpu-timers: Cleanup CPU timers before freeing them during exec Commit 55e8c8eb2c7b ("posix-cpu-timers: Store a reference to a pid not a task") started looking up tasks by PID when deleting a CPU timer. When a non-leader thread calls execve, it will switch PIDs with the leader process. Then, as it calls exit_itimers, posix_cpu_timer_del cannot find the task because the timer still points out to the old PID. That means that armed timers won't be disarmed, that is, they won't be removed from the timerqueue_list. exit_itimers will still release their memory, and when that list is later processed, it leads to a use-after-free. Clean up the timers from the de-threaded task before freeing them. This prevents a reported use-after-free.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

A Linux kernel bug can leave POSIX CPU timers linked after their memory is freed during exec by a non-leader thread. Later timer processing can trigger a use-after-free. The sources identify affected kernel data and stable fix references, but do not provide CVSS, CWE, impact category, or exploitation evidence.

Executive priority

Do not treat this as an emergency based solely on current evidence, but include it in kernel patch planning. Escalate for shared Linux systems or if vendor advisories assign higher severity.

Technical view

After commit 55e8c8eb2c7b, CPU timer deletion looks up tasks by PID. During execve from a non-leader thread, PID switching can make posix_cpu_timer_del miss the task, leaving armed timers on timerqueue_list. exit_itimers then releases timer memory; later list processing can use freed memory. The fix cleans timers before freeing them.

Likely exposure

Exposure is limited to Linux kernels matching the affected data and missing the referenced stable fixes. The bundle lists Linux 5.7, 5.10.137, 5.15.61, 5.18.18, 5.19.2, and 6.0 data points, but distribution backports may differ.

Exploitation context

CISA KEV status is false in the bundle. Sources describe a reported use-after-free, but do not cite active exploitation, public exploit availability, required privileges, remote reachability, or reliable impact. Treat exploitation status as unconfirmed.

Researcher notes

The root cause is a stale PID reference after de-threading during execve. The timer remains queued despite memory release in exit_itimers, creating a deferred use-after-free. Missing evidence includes exploit primitives, privilege requirements, crashability versus code execution, and distributor-specific affected kernels.

Mitigation direction

  • Apply vendor or distribution kernel updates that include the referenced stable fixes.
  • For custom kernels, review the relevant upstream stable commit for your maintained branch.
  • Track Linux vendor advisories for affected product mappings and operational guidance.
  • Schedule kernel replacement and reboot according to your normal patch process.

Validation and detection

  • Inventory running Linux kernel versions across servers, appliances, images, and VM templates.
  • Map each kernel to vendor advisories or the upstream stable commit list.
  • Confirm whether the posix-cpu-timers cleanup fix is present in each maintained build.
  • Record KEV status as not listed unless later authoritative sources change.
  • Retest affected systems after update using normal workload and stability checks.
Prepared
Confidence
medium
Sources
7

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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CVE-2022-50095 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
0ADP providers
6Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux55e8c8eb2c7b6bf30e99423ccfe7ca032f498f59, 55e8c8eb2c7b6bf30e99423ccfe7ca032f498f59, 55e8c8eb2c7b6bf30e99423ccfe7ca032f498f59, 55e8c8eb2c7b6bf30e99423ccfe7ca032f498f59, 55e8c8eb2c7b6bf30e99423ccfe7ca032f498f59unaffected
LinuxLinux5.7, 0, 5.10.137, 5.15.61, 5.18.18, 5.19.2, 6.0affected
Weakness

CWE details

No CWE listed

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