Use-after-free in Linux kernel - CVE-2026-89658
Published: September 12, 2026
Vulnerability identifier: #VU149140
CSH Severity: Low
CVSS v4: 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]
CVE-ID: CVE-2026-89658
CWE-ID: CWE-416
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
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.
Affected software
Linux kernel
How to mitigate CVE-2026-89658
Install security update from vendor's repository.