PT-2026-8120 · Linux · Linux Kernel

Published

2026-01-01

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Updated

2026-02-14

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CVE-2026-23127

CVSS v3.1

5.5

Medium

VectorAV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)
Description The Linux kernel contains an issue related to reference counting within the perf subsystem. Specifically, a warning occurs when incrementing the mmap count of a perf event. This happens when creating a group member event with the PERF FLAG FD OUTPUT flag after the group leader has been mapped. The issue arises because perf mmap rb() attempts to increment event->mmap count when it is already zero, leading to a use-after-free warning. The problem is triggered by a specific sequence of system calls involving perf event open and mmap. The root cause is that the output event is copied in perf event set output(), setting event->rb, which then leads to the problematic increment in perf mmap rb(). The fix prevents the increment when event->mmap count is zero, also preventing multiple events from updating the same user page.
Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Exploit

Related Identifiers

CVE-2026-23127

Affected Products

Linux Kernel