Use-after-free in Linux kernel - CVE-2026-89659
Published: September 12, 2026
Vulnerability identifier: #VU149141
CSH Severity: Low
CVSS v4: 0 [CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-89659
CWE-ID: CWE-416
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to trigger a use-after-free.
The vulnerability exists due to a use-after-free in NFSD delegation revocation when an expired recalled delegation is revoked concurrently with client teardown. A remote user can race delegation revocation with client teardown to trigger a use-after-free.
During the race window, the delegation is on neither the client's active-delegation list nor revoked-delegation list.
Affected software
Linux kernel
How to mitigate CVE-2026-89659
Install security update from vendor's repository.