Description
In MIT Kerberos 5 (aka krb5) before 1.22.3, there is a NULL pointer dereference 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, causing the process to terminate in parse_nego_message.
Affected products
mit: kerberos 5
References7
- web.mit.edu/kerberos/advisories/ Vendor Advisory
- cems.fun/2026/04/27/krb5-two-unauthenticated-network-vulnerabil… ExploitPatchThird Party Advisory
- github.com/krb5/krb5/commit/2e75f0d9362fb979f5fc92829431a590a13… Patch
- cems.fun/2026/04/27/krb5-two-unauthenticated-network-vulnerabil… ExploitPatchThird Party Advisory
- cert-portal.siemens.com/productcert/html/ssa-019113.html
- cert-portal.siemens.com/productcert/html/ssa-082556.html
- cert-portal.siemens.com/productcert/html/ssa-457936.html
Metrics
- CVSS 3.1
-
7.5
HIGH
Score source: NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - EPSS — exploit probability
- 1% percentile: 52 · as of 13 November 2026
- CWE
- CWE-476
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.