SB20260912117 - Use-after-free in Linux kernel nfsd
Published: September 12, 2026
Security Bulletin ID
SB20260912117
CSH Severity
Low
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Local access
Highest impact
Information disclosure
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Use-after-free (CVE-ID: CVE-2026-89658)
CWE-ID: CWE-416 - Use After Free
CVSSv4: 0 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a local user to trigger a use-after-free condition.
The vulnerability exists due to improper object lifetime management in the NFSD NFSv4 revoked-state cleanup function nfs40_clean_admin_revoked() when periodic revoked-state cleanup races client expiration. A local user can trigger client expiration by writing to the clients/ctl file to trigger a use-after-free condition.
Remediation
Install update from vendor's website.