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Vulnerability record · CVE-2026-40355 · published 28 April 2026

CVE-2026-40355: Mit kerberos 5 null pointer dereference vulnerability

Mit · Kerberos 5

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.

7.5 CVSS 3.1 High EPSS 0.79% · top 45.5% CWE-476 · NULL pointer dereference
7.5CVSS 3.1 base score
0.79%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
6References, 2 tagged exploit
14 Jul 2026Last modified by NVD

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.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://cems.fun/2026/04/27/krb5-two-unauthenticated-network-vulnerabilities.html ExploitPatchThird Party Advisory
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 ExploitPatchThird Party Advisory
https://cert-portal.siemens.com/productcert/html/ssa-019113.html
https://cert-portal.siemens.com/productcert/html/ssa-082556.html

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-40355), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.