CVE-2026-89791

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description A use-after-free issue exists in the Linux kernel's perf subsystem. The problem occurs when a perf mmap() revival races with the last munmap(). Specifically, the perf mmap close() function drops rb->mmap count without holding the event->mmap mutex. This creates a window where a concurrent perf mmap rb() can execute its revival path, leading to a situation where the close operation frees a newly revived buffer while another process still has it mapped. This page-level use-after-free can allow an unprivileged local user to escalate privileges to root.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.