CVE-2026-40355 — Null Pointer Dereference
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
What This Means For You
- If your environment is affected by CWE-476, review your exposure and prioritize patching based on your environment. Monitor vendor advisories for CVE-2026-40355 updates and patches.
Related ATT&CK Techniques
🛡️ Detection Rules
3 rules · 6 SIEM formats3 detection rules auto-generated for this incident, mapped to MITRE ATT&CK. Sigma YAML is free — export to any SIEM format via the Intel Bot.
CVE-2026-40355 - Kerberos Null Pointer Dereference via gss_accept_sec_context
title: CVE-2026-40355 - Kerberos Null Pointer Dereference via gss_accept_sec_context
id: scw-2026-04-28-ai-1
status: experimental
level: critical
description: |
Detects the execution of the Kerberos Key Distribution Center (KDC) process with arguments or calls that suggest an attempt to exploit CVE-2026-40355. This vulnerability involves a NULL pointer dereference in `gss_accept_sec_context()` when a NegoEx mechanism is registered, potentially leading to a denial of service. This rule specifically targets the Kerberos KDC process and the function call associated with the vulnerability.
author: SCW Feed Engine (AI-generated)
date: 2026-04-28
references:
- https://shimiscyberworld.com/posts/nvd-CVE-2026-40355/
tags:
- attack.initial_access
- attack.t1190
logsource:
category: process_creation
detection:
selection:
Image|contains:
- '/usr/sbin/krb5kdc'
- '/usr/kerberos/sbin/krb5kdc'
CommandLine|contains:
- 'gss_accept_sec_context()'
condition: selection
falsepositives:
- Legitimate administrative activity
Source: Shimi's Cyber World · License & reuse
Indicators of Compromise
| ID | Type | Indicator |
|---|---|---|
| CVE-2026-40355 | vulnerability | CVE-2026-40355 |
| CWE-476 | weakness | CWE-476 |
Written by SCW Vulnerability Desk
Source & Attribution
| Source Platform | NVD |
| Channel | National Vulnerability Database |
| Published | April 28, 2026 at 09:16 UTC |
This content was curated and summarized by Shimi's Cyber World for informational purposes. It is not copied or republished in full. All intellectual property rights remain with the original author and source.
Believe this infringes your rights? Submit a takedown request.
Related coverage
CVE-2026-7234: Path Traversal Flaw in BrowserOperator Core Exposes Users
CVE-2026-7234 — A weakness has been identified in BrowserOperator browser-operator-core up to 0.6.0. Affected is the function startsWith of the file scripts/component_server/server.js. Executing a manipulation...
CVE-2026-7230 — SourceCodester Safety Anger Pad Vulnerability
CVE-2026-7230 — A vulnerability was found in SourceCodester Safety Anger Pad 1.0. The affected element is an unknown function. The manipulation of the argument angerDisplay...
CVE-2026-7229 — Code-Projects Coaching Management System SQL Injection
CVE-2026-7229 — A vulnerability was found in code-projects Coaching Management System 1.0. This affects an unknown function of the file /cims/modules/admin/reply.php of the component POST...