Improper input validation in Linux kernel - CVE-2026-89538
Published: September 12, 2026
Vulnerability identifier: #VU149272
CSH Severity: Low
CVSS v4: 5.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-89538
CWE-ID: CWE-20
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to cause a denial of service.
The vulnerability exists due to improper input validation in gss_krb5_unwrap_v2() when processing Kerberos v2 wrap tokens with oversized extra count fields. A remote user can send a malformed Kerberos v2 wrap token to cause a denial of service.
The token must be encrypted using a valid GSS context.
Affected software
Linux kernel
How to mitigate CVE-2026-89538
Install security update from vendor's repository.