CVE-2026-76781

A flaw was found in libxml2. A local user or an attacker providing a specially crafted XML catalog can trigger a NULL pointer dereference during XML catalog parsing. This occurs when a nextCatalog element lacks its mandatory catalog attribute, leading to the application crashing and causing a Denial of Service (DoS).

This Moderate flaw in libxml2's XML catalog parsing can lead to a denial of service. The vulnerability requires user interaction, as a specially crafted XML catalog with a missing catalog attribute in a nextCatalog element must be processed by an application using libxml2, causing it to crash. This limits the attack surface to scenarios where an attacker can provide malicious XML input to a vulnerable application.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

To mitigate this issue, avoid processing untrusted XML catalog files with applications linked against libxml2. Users should exercise caution when opening or processing XML documents from untrusted sources, as a malicious catalog could lead to application crashes. Where possible, restrict the ability of applications to load external XML catalogs, or ensure that only trusted catalog files are used.