Use-after-free in Linux kernel - CVE-2026-89791
Published: September 17, 2026
Vulnerability identifier: #VU150502
CSH Severity: Low
CVSS v4: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-89791
CWE-ID: CWE-416
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to escalate privileges.
The vulnerability exists due to use-after-free in perf event ring buffer handling when perf mmap revival races with the last munmap. A local user can race perf mmap and munmap operations to escalate privileges.
The issue is reachable by an unprivileged user under the default kernel.perf_event_paranoid=2 setting.
Affected software
Linux kernel
How to mitigate CVE-2026-89791
Install security update from vendor's repository.