Improper Validation of Specified Quantity in Input in Linux kernel - CVE-2026-89666
Published: September 12, 2026
Vulnerability identifier: #VU149132
CSH Severity: Medium
CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-89666
CWE-ID: CWE-1284
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to corrupt on-disk timestamp metadata.
The vulnerability exists due to improper validation of specified quantities in input in NFSv3 SETATTR and create operation handlers when processing client-supplied atime or mtime values with an out-of-range nanoseconds field. A remote attacker can send specially crafted NFSv3 SETATTR, CREATE, MKDIR, SYMLINK, or MKNOD requests to corrupt on-disk timestamp metadata.
Affected filesystems include ext4 and XFS with bigtime support.
Affected software
Linux kernel
How to mitigate CVE-2026-89666
Install security update from vendor's repository.