CVE-2025-40327
Description
A flaw was found in the Linux kernel's perf subsystem. When using cpu-clock events, the __perf_event_overflow() callback is invoked from an hrtimer handler. This callback attempts to stop the event by calling cpu_clock_event_stop(), which in turn calls hrtimer_cancel() to cancel the hrtimer. This results in recursive entry into the hrtimer code from within an hrtimer handler, causing a deadlock and system hang. A local user with the ability to create perf events could exploit this to cause a denial of service.
Statement
This issue affects systems where local users can create perf cpu-clock events. The vulnerability requires local access and the ability to use the perf_event_open() system call, which may be restricted by the kernel.perf_event_paranoid sysctl setting. Exploitation leads to a system hang requiring a reboot to recover.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.5 | N/A | N/A |
| Attack Vector | Local | N/A | N/A |
| Attack Complexity | High | N/A | N/A |
| Privileges Required | Low | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | Low | N/A | N/A |
| Integrity Impact | High | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:H
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