CVE-2025-37747

Published May 1, 2025

Last updated 2 days ago

CVSS medium 5.5

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: perf: Fix hang while freeing sigtrap event Perf can hang while freeing a sigtrap event if a related deferred signal hadn't managed to be sent before the file got closed: perf_event_overflow() task_work_add(perf_pending_task) fput() task_work_add(____fput()) task_work_run() ____fput() perf_release() perf_event_release_kernel() _free_event() perf_pending_task_sync() task_work_cancel() -> FAILED rcuwait_wait_event() Once task_work_run() is running, the list of pending callbacks is removed from the task_struct and from this point on task_work_cancel() can't remove any pending and not yet started work items, hence the task_work_cancel() failure and the hang on rcuwait_wait_event(). Task work could be changed to remove one work at a time, so a work running on the current task can always cancel a pending one, however the wait / wake design is still subject to inverted dependencies when remote targets are involved, as pictured by Oleg: T1 T2 fd = perf_event_open(pid => T2->pid); fd = perf_event_open(pid => T1->pid); close(fd) close(fd) <IRQ> <IRQ> perf_event_overflow() perf_event_overflow() task_work_add(perf_pending_task) task_work_add(perf_pending_task) </IRQ> </IRQ> fput() fput() task_work_add(____fput()) task_work_add(____fput()) task_work_run() task_work_run() ____fput() ____fput() perf_release() perf_release() perf_event_release_kernel() perf_event_release_kernel() _free_event() _free_event() perf_pending_task_sync() perf_pending_task_sync() rcuwait_wait_event() rcuwait_wait_event() Therefore the only option left is to acquire the event reference count upon queueing the perf task work and release it from the task work, just like it was done before 3a5465418f5f ("perf: Fix event leak upon exec and file release") but without the leaks it fixed. Some adjustments are necessary to make it work: * A child event might dereference its parent upon freeing. Care must be taken to release the parent last. * Some places assuming the event doesn't have any reference held and therefore can be freed right away must instead put the reference and let the reference counting to its job.
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Modified
Products
linux_kernel

Risk scores

CVSS 3.1

Type
Primary
Base score
5.5
Impact score
3.6
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Severity
MEDIUM

Weaknesses

nvd@nist.gov
NVD-CWE-noinfo

Social media

Hype score
Not currently trending

  1. The Tension Over CVE-2025-37747: Urgency, Exploitation, and Ethical Risks https://t.co/dm0hvUWE9H

    @cyber_newsroom

    29 Jun 2026

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  2. CVE-2025-37747: A Serious Oversight in Microsoft’s Performance Security https://t.co/SzP4maY1VR

    @cyber_newsroom

    29 Jun 2026

    2 Impressions

    1 Retweet

    1 Like

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  3. A Silent Threat: How CVE-2025-37747 Could Hang Your Defenses https://t.co/AOZvVyaxGh

    @cyber_newsroom

    29 Jun 2026

    1 Impression

    1 Retweet

    1 Like

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  4. CVE-2025-37747: Don't Get Caught in a Performance Hang-Up https://t.co/eUl3L4Tiwf

    @cyber_newsroom

    29 Jun 2026

    1 Impression

    1 Retweet

    1 Like

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  5. CVE-2025-37747 In the Linux kernel, the following vulnerability has been resolved: perf: Fix hang while freeing sigtrap event Perf can hang while freeing a sigtrap event if a rela… https://t.co/777cvRBhY4

    @CVEnew

    1 May 2025

    217 Impressions

    0 Retweets

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Configurations

Related CVEs

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References

Sources include official advisories and independent security research.