SB2026091278 - Improper input validation in Linux kernel nfsd
Published: September 12, 2026
Security Bulletin ID
SB2026091278
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Remote access
Highest impact
Data manipulation
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Improper input validation (CVE-ID: CVE-2026-89701)
CWE-ID: CWE-20 - Improper input validation
CVSSv4: 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]
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.
Remediation
Install update from vendor's website.