Out-of-bounds read in Linux kernel - CVE-2026-89542

Vulnerability details

The vulnerability allows a remote user to cause a denial of service.

The vulnerability exists due to improper length validation in gss_krb5_unwrap_v2() and its rotation helpers when processing a short or malformed GSS token. A remote user can provide a token shorter than the required header or with a declared length exceeding the buffer bounds to cause a denial of service.

The flawed length arithmetic can result in an out-of-bounds read, an unsigned underflow during cleanup, or a divide-by-zero during buffer rotation.

Affected software

How to mitigate CVE-2026-89542

External References

• https://git.kernel.org/stable/c/6959297aaa9572783d620a226d73c3fb94494888
• https://git.kernel.org/stable/c/806584a4b67a7233870c33e5b8f872e76dd02988
• https://git.kernel.org/stable/c/a7894e10572d53eb10109b8d07459cc8d3435811
• https://git.kernel.org/stable/c/dddcb0f4b7e27fac16a78ea9a1c8ec2e8a241087

Related Security Bulletins

• Out-of-bounds read in Linux kernel sunrpc auth_gss