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EUVD-2026-365138

European Vulnerability Database identifier assigned by ENISA

Reserved

2026-10-02 08:34

Assigner

ENISA

Alias of

a CVE record, shown under related vulnerabilities. This identifier carries no description, severity or references of its own: they belong to that CVE.

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{
  "assigner": "ENISA",
  "date_reserved": "2026-10-02T08:34:54.055249+00:00",
  "id": "EUVD-2026-365138"
}

CVE-2025-38352 (GCVE-0-2025-38352)

Vulnerability from cvelistv5 – Published: 2025-07-22 08:04 – Updated: 2026-09-08 15:32

Title

posix-cpu-timers: fix race between handle_posix_cpu_timers() and posix_cpu_timer_del()

Summary

In the Linux kernel, the following vulnerability has been resolved: posix-cpu-timers: fix race between handle_posix_cpu_timers() and posix_cpu_timer_del() If an exiting non-autoreaping task has already passed exit_notify() and calls handle_posix_cpu_timers() from IRQ, it can be reaped by its parent or debugger right after unlock_task_sighand(). If a concurrent posix_cpu_timer_del() runs at that moment, it won't be able to detect timer->it.cpu.firing != 0: cpu_timer_task_rcu() and/or lock_task_sighand() will fail. Add the tsk->exit_state check into run_posix_cpu_timers() to fix this. This fix is not needed if CONFIG_POSIX_CPU_TIMERS_TASK_WORK=y, because exit_task_work() is called before exit_notify(). But the check still makes sense, task_work_add(&tsk->posix_cputimers_work.work) will fail anyway in this case.

Severity

7.8 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

SSVC

Exploitation: active Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2025-09-05 03:55 UTC

CWE

CWE-367 - Time-of-check Time-of-use (TOCTOU) Race Condition

Assigner

Linux mitre root Scorecard

References

12 references

URL	Tags
https://git.kernel.org/stable/c/78a4b8e3795b31dae…
https://git.kernel.org/stable/c/c076635b3a42771ac…
https://git.kernel.org/stable/c/2f3daa04a9328220d…
https://git.kernel.org/stable/c/764a7a5dfda23f699…
https://git.kernel.org/stable/c/2c72fe18cc5f9f175…
https://git.kernel.org/stable/c/c29d5318708e67ac1…
https://git.kernel.org/stable/c/460188bc042a3f40f…
https://git.kernel.org/stable/c/f90fff1e152dedf52…
https://www.cisa.gov/known-exploited-vulnerabilit…	government-resource
https://github.com/farazsth98/chronomaly	exploit
https://lists.debian.org/debian-lts-announce/2025…
https://lists.debian.org/debian-lts-announce/2025…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 0bdd2ed4138ec04e09b4f8165981efc99e439f55 , < 78a4b8e3795b31dae58762bc091bb0f4f74a2200 (git) Affected: 0bdd2ed4138ec04e09b4f8165981efc99e439f55 , < c076635b3a42771ace7d276de8dc3bc76ee2ba1b (git) Affected: 0bdd2ed4138ec04e09b4f8165981efc99e439f55 , < 2f3daa04a9328220de46f0d5c919a6c0073a9f0b (git) Affected: 0bdd2ed4138ec04e09b4f8165981efc99e439f55 , < 764a7a5dfda23f69919441f2eac2a83e7db6e5bb (git) Affected: 0bdd2ed4138ec04e09b4f8165981efc99e439f55 , < 2c72fe18cc5f9f1750f5bc148cf1c94c29e106ff (git) Affected: 0bdd2ed4138ec04e09b4f8165981efc99e439f55 , < c29d5318708e67ac13c1b6fc1007d179fb65b4d7 (git) Affected: 0bdd2ed4138ec04e09b4f8165981efc99e439f55 , < 460188bc042a3f40f72d34b9f7fc6ee66b0b757b (git) Affected: 0bdd2ed4138ec04e09b4f8165981efc99e439f55 , < f90fff1e152dedf52b932240ebbd670d83330eca (git)
Linux	Linux	Affected: 2.6.36 Unaffected: 0 , < 2.6.36 (semver) Unaffected: 5.4.295 , ≤ 5.4.* (semver) Unaffected: 5.10.239 , ≤ 5.10.* (semver) Unaffected: 5.15.186 , ≤ 5.15.* (semver) Unaffected: 6.1.142 , ≤ 6.1.* (semver) Unaffected: 6.6.94 , ≤ 6.6.* (semver) Unaffected: 6.12.34 , ≤ 6.12.* (semver) Unaffected: 6.15.3 , ≤ 6.15.* (semver) Unaffected: 6.16 , ≤ * (original_commit_for_fix)

Show details on NVD website

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                "id": "CVE-2025-38352",
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                "timestamp": "2025-09-05T03:55:31.566379Z",
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              "value": "AV:L - The vulnerability is reached purely through local syscalls \u2014 `timer_create`/`timer_settime`/`timer_delete` (or `clock_nanosleep`) plus `ptrace`/`waitpid` to control task reaping \u2014 with the trigger arriving via the local timer tick. There is no network-facing path into posix-cpu-timers.\nAC:L - The attacker controls both sides of the race: it arms the CPU timer expiry, chooses the precise moment of `release_task()` by calling `waitpid()` from its own parent/tracer, and issues the concurrent `timer_delete()` from a sibling thread \u2014 retryable in a tight loop and widenable by queueing up to 20 timers on the firing list. Real-world exploitation of this exact bug confirms it is reliably winnable.\nPR:L - No capability or permission check exists anywhere on the path \u2014 `validate_clock_permissions()`/`pid_for_clock()` gate only on thread-group/pid existence, and `grep` for `capable`/`CAP_` in both posix-timers files returns nothing. Any unprivileged local user, including a seccomp-confined Android app UID, can reach it.\nUI:N - The attacker\u0027s own processes and threads perform every step \u2014 creating the timer, exiting the traced thread, reaping it, and deleting the timer. No victim action of any kind is needed.\nS:U - The use-after-free corrupts kernel heap objects and escalates within the kernel\u0027s own security authority, which is standard kernel privilege escalation. No hypervisor, IOMMU, or other security-authority boundary is crossed.\nC:H - The freed `struct sigqueue` is linked into the signal pending list by `send_sigqueue()` and later copied out to userspace through `dequeue_signal()`/`rt_sigtimedwait()`, disclosing whatever now occupies the reclaimed slab object \u2014 an effectively arbitrary kernel-memory read. The `do_cpu_nanosleep()` variant additionally exposes reclaimed kernel stack.\nI:H - `send_sigqueue()` writes into the freed object (`q-\u003einfo.si_overrun++`) and performs a `list_add_tail()` linked-list insertion on attacker-resprayable memory, followed by a double free on dequeue \u2014 a classic controlled-write primitive leading to full privilege escalation, as demonstrated by in-the-wild exploitation of this flaw.\nA:H - Even without successful exploitation the race causes `BUG_ON(!(q-\u003eflags \u0026 SIGQUEUE_PREALLOC))` in `send_sigqueue()`, `WARN_ON_ONCE()` in the delete path, list corruption, and a double free \u2014 any of which oops or panic the kernel. Spinning the race is trivially repeatable as a denial of service."
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    "state": "PUBLISHED"
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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

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EUVD-2026-365138

CVE-2025-38352 (GCVE-0-2025-38352)

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