CVE-2026-40356

State: Published
Severity: 5.9 Medium
Published: Apr 28, 2026
Updated: Apr 28, 2026
Reserved: Apr 11, 2026

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.

Scores

CVSS	Score	Vector	Source
3.1	5.9 Medium	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H	mitre

Weaknesses

CWE-191 Integer Underflow (Wrap or Wraparound)

Affected Products

Product	Versions
Kerberos 5MIT	1.18 to before 1.22.3Affected

References

https://web.mit.edu/kerberos/advisories/
https://cems.fun/2026/04/27/krb5-two-unauthenticated-network-vulnerabilities.html
https://github.com/krb5/krb5/commit/2e75f0d9362fb979f5fc92829431a590a130929f

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