SB20260917180 - Use-after-free in Linux kernel events
Published: September 17, 2026
Security Bulletin ID
SB20260917180
CSH Severity
Low
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Local access
Highest impact
Code execution
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Use-after-free (CVE-ID: CVE-2026-89791)
CWE-ID: CWE-416 - Use After Free
CVSSv4: 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]
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.
Remediation
Install update from vendor's website.