CVE-2026-40355

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.

CVSS v3 5.9 MEDIUM

5.9^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.2 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://cems.fun/2026/04/27/krb5-two-unauthenticated-network-vulnerabilities.html	Exploit Third Party Advisory Patch
https://github.com/krb5/krb5/commit/2e75f0d9362fb979f5fc92829431a590a130929f	Patch
https://web.mit.edu/kerberos/advisories/	Vendor Advisory
https://cems.fun/2026/04/27/krb5-two-unauthenticated-network-vulnerabilities.html	Exploit Third Party Advisory Patch

Configurations

Configuration 1 (hide)

cpe:2.3:a:mit:kerberos_5:*:*:*:*:*:*:*:*

History

08 Jul 2026, 12:48

Type	Values Removed	Values Added
CPE		cpe:2.3:a:mit:kerberos_5::::::::
References	~~() https://cems.fun/2026/04/27/krb5-two-unauthenticated-network-vulnerabilities.html -~~	() https://cems.fun/2026/04/27/krb5-two-unauthenticated-network-vulnerabilities.html - Exploit, Third Party Advisory, Patch
References	~~() https://github.com/krb5/krb5/commit/2e75f0d9362fb979f5fc92829431a590a130929f -~~	() https://github.com/krb5/krb5/commit/2e75f0d9362fb979f5fc92829431a590a130929f - Patch
References	~~() https://web.mit.edu/kerberos/advisories/ -~~	() https://web.mit.edu/kerberos/advisories/ - Vendor Advisory
First Time		Mit Mit kerberos 5

28 Apr 2026, 14:16

Type	Values Removed	Values Added
References	~~() https://cems.fun/2026/04/27/krb5-two-unauthenticated-network-vulnerabilities.html -~~	() https://cems.fun/2026/04/27/krb5-two-unauthenticated-network-vulnerabilities.html -

28 Apr 2026, 06:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-04-28 06:16

Updated : 2026-07-08 12:48

NVD link : CVE-2026-40355

Mitre link : CVE-2026-40355

CVE.ORG link : CVE-2026-40355

JSON object : View

Products Affected

mit

kerberos_5

CWE

CWE-476

NULL Pointer Dereference

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