CVE-2026-40355

MEDIUM

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 v3.1 Score

5.9
MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Published: 4/28/2026Modified: 7/14/2026

Related Intelligence (1)

CRITICALAi

Siemens SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP

<p><a href="https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-209-04.json"><strong>View CSAF</strong></a></p> <h2>Summary</h2> <p><strong>Multiple vulnerabilities have been identified in the additional GNU/Linux subsystem of the firmware version V3.1.6 for the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP (incl. SIPLUS variant). Siemens is preparing fix versions and recommend

CVE-2021-41617CVE-2023-28531
CISA Advisories

References (6)

https://cems.fun/2026/04/27/krb5-two-unauthenticated-network-vulnerabilities.htmlExploitPatchhttps://github.com/krb5/krb5/commit/2e75f0d9362fb979f5fc92829431a590a130929fPatchhttps://web.mit.edu/kerberos/advisories/Vendor Advisoryhttps://cems.fun/2026/04/27/krb5-two-unauthenticated-network-vulnerabilities.htmlExploitPatchhttps://cert-portal.siemens.com/productcert/html/ssa-019113.htmlhttps://cert-portal.siemens.com/productcert/html/ssa-082556.html