Improper input validation in Linux kernel - CVE-2026-89701
Published: September 12, 2026
Vulnerability identifier: #VU149101
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-2026-89701
CWE-ID: CWE-20
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to write malformed timestamps to disk.
The vulnerability exists due to improper input validation in the TIME_DELEG_ACCESS and TIME_DELEG_MODIFY decode paths in nfs4xdr.c and nfs4callback.c when decoding TIME_DELEG timestamp attributes. A remote attacker can submit malformed TIME_DELEG timestamp attributes to write malformed timestamps to disk.
Affected software
Linux kernel
How to mitigate CVE-2026-89701
Install security update from vendor's repository.