Time-of-check Time-of-use (TOCTOU) Race Condition in Linux kernel - CVE-2026-89713
Published: September 12, 2026
Vulnerability identifier: #VU149096
CSH Severity: Medium
CVSS v4: 6 [CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-89713
CWE-ID: CWE-367
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to truncate append-only files.
The vulnerability exists due to a time-of-check to time-of-use race condition in nfsd_setattr() when handling SETATTR size updates for append-only files. A remote user can issue a SETATTR request that races with a concurrent append to truncate append-only files.
Affected software
Linux kernel
How to mitigate CVE-2026-89713
Install security update from vendor's repository.