CVE-2026-40356

medium

Description

In MIT Kerberos 5 (aka krb5) before 1.22.3, there is an integer underflow and resultant out-of-bounds read if an application calls gss_accept_sec_context() on a system with a NegoEx mechanism registered in /etc/gss/mech. An unauthenticated remote attacker can trigger this, possibly causing the process to terminate in parse_message.

References

https://web.mit.edu/kerberos/advisories/

https://github.com/krb5/krb5/commit/2e75f0d9362fb979f5fc92829431a590a130929f

https://cems.fun/2026/04/27/krb5-two-unauthenticated-network-vulnerabilities.html

Details

Source: Mitre, NVD

Published: 2026-04-28

Updated: 2026-04-28

Risk Information

CVSS v2

Base Score: 5.4

Vector: CVSS2#AV:N/AC:H/Au:N/C:N/I:N/A:C

Severity: Medium

CVSS v3

Base Score: 5.9

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Severity: Medium