High

NULL Pointer Dereference in Apache HTTP Server mod_dav_lock

IdentifiersCVE-2026-29169CWE-476· NULL Pointer Dereference

CVE-2026-29169 is a NULL pointer dereference vulnerability in the mod_dav_lock module of Apache HTTP Server. It affects Apache HTTP Server 2.4.66 and earlier. A maliciously crafted request can trigger a NULL pointer dereference in mod_dav_lock, causing the affected server process to crash. Apache states that mod_dav_lock is not used internally by mod_dav or mod_dav_fs, and that its only known use case was mod_dav_svn from Apache Subversion versions earlier than 1.2.0. The issue was fixed in the 2.4.x branch in revision r1933354 and released in Apache HTTP Server 2.4.67.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation results in denial of service through a crash of the Apache HTTP Server process handling the request. Available scoring and vendor context indicate no demonstrated confidentiality or integrity impact; the primary effect is loss of availability. The issue is described as remotely reachable over the network, requiring no privileges and no user interaction, and can cause high availability impact on the affected component.

Mitigation

If you can’t patch tonight, do this now.

As an interim mitigation, unload or remove mod_dav_lock from the Apache configuration if it is not explicitly required. This is particularly practical because Apache states the module is not used internally by mod_dav or mod_dav_fs, and its only known use case was legacy mod_dav_svn support from Apache Subversion versions earlier than 1.2.0. Limiting exposure of affected HTTP services until patching is completed may further reduce risk, but the primary mitigation in the provided content is removal of mod_dav_lock.

Remediation

Patch, then assume compromise.

Upgrade Apache HTTP Server to version 2.4.67 or later, which contains the fix for CVE-2026-29169. If the environment still loads mod_dav_lock and cannot be upgraded immediately, remove or disable mod_dav_lock where it is not required. Apache specifically notes that mod_dav_lock is not used internally by mod_dav or mod_dav_fs, reducing the likelihood that it is needed in most deployments.

PUBLIC EXPLOITS

Exploits

No valid public exploits. Mallory filtered out 2 candidates as fakes, detection scripts, or README-only repos.

VALID 0 / 2 TOTALView more in app

All candidate exploits were filtered out by Mallory's validation.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType

Apache Software FoundationHttp Serverapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

15 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

15 SOURCESView more in app

msrc microsoftNews

May 7, 2026

CVE-2026-29169 - Security Update Guide - Microsoft - Apache HTTP Server: mod_dav_lock indirect lock crash

A NULL pointer dereference vulnerability in Apache HTTP Server's mod_dav_lock that can be exploited remotely over the network to cause a denial of service via crash, with high availability impact.

thecybersecguruNews

May 5, 2026

Apache HTTP Server RCE Vulnerability: Critical Patch for CVE-2026-23918 | The CyberSec Guru

A NULL pointer dereference vulnerability in Apache HTTP Server mod_dav_lock that allows an unauthenticated attacker to crash the server process.

cyber security newsNews

May 5, 2026

Critical Apache HTTP Server Flaw Exposes Millions of Servers to Remote Code Execution Attacks

A low-severity NULL pointer dereference denial-of-service vulnerability in Apache HTTP Server mod_dav_lock that can crash the server.

opennetNews

Dec 25, 2025

� Apache httpd 2.4.67 �� HTTP/2, �� ̣��

Apache HTTP Server mod_dav_lock vulnerability involving improper handling that could be abused for denial of service or related impact.

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.

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Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity9

Community discussion across Reddit, Mastodon, and other social sources.

EXTERNAL REFERENCES

MITRE CVE

cve.org · CVE-2026-29169

NVD

nvd.nist.gov/vuln/detail/CVE-2026-29169

MITRE CWE · CWE-476

NULL Pointer Dereference

Vendor Advisory

httpd.apache.org/security/vulnerabilities_24.html

Third Party Advisory

openwall.com/lists/oss-security/2026/05/04/20

openwall.com

openwall.com/lists/oss-security/2026/05/05/12