MIT Kerberos 5 (krb5) through 1.22.2 contains a NULL pointer dereference in make_cred_list() in rd_cred.c that allows authenticated Kerberos clients to crash services by sending mismatched KRB-CRED arrays. Attackers can send forwarded credentials with more tickets than ticket_info entries through gss_accept_sec_context() to crash GSS-API acceptor services, causing denial of service.
Fix
Microsoft's update · Moderate
- Release Notes — azl3 krb5 1.21.3-5 on Azure Linux 3.0 · build 1.21.3-6
From the 2026-Oct release note of Microsoft's Security Update Guide, revised 2026-10-29.
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 7.1NVD modified 2026-10-09 12:17
Affected (CPE criteria) 0
NVD has not attached CPE configurations yet.
References 6
- https://github.com/krb5/krb5
- https://github.com/krb5/krb5/blob/krb5-1.22.2-final/src/lib/krb5/krb/rd_cred.c#L77-L112
- https://github.com/krb5/krb5/commit/48afa9abb89ab2176bb20624d87d010b9984fc08
- https://github.com/krb5/krb5/commit/62196e2b269159a5465f5b8d0ed7cf6f29c3282a
- https://github.com/krb5/krb5/pull/1511
- https://www.vulncheck.com/advisories/mit-krb5-through-1.22.2-null-pointer-dereference-via-krb5-rd-cred