Vulnerability 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.
CVSS Score
MEDIUM
Related Weaknesses (CWE)
References
- https://cems.fun/2026/04/27/krb5-two-unauthenticated-network-vulnerabilities.htm
- https://github.com/krb5/krb5/commit/2e75f0d9362fb979f5fc92829431a590a130929f
- https://web.mit.edu/kerberos/advisories/
FAQ
What is CVE-2026-40356?
CVE-2026-40356 is a vulnerability with a CVSS score of 5.9 (MEDIUM). 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 register...
How severe is CVE-2026-40356?
CVE-2026-40356 has been rated MEDIUM with a CVSS base score of 5.9/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-40356?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.