libxml2 NULL Pointer Deref in XML Catalog Parsing (DoS)
CVE-2026-76781 Published on September 17, 2026

Libxml2: libxml2: null pointer dereference parsing nextcatalog without catalog attribute
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).

Vendor Advisory NVD

Vulnerability Analysis

CVE-2026-76781 can be exploited with local system access, requires user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.

Attack Vector:
LOCAL
Attack Complexity:
LOW
Privileges Required:
NONE
User Interaction:
REQUIRED
Scope:
UNCHANGED
Confidentiality Impact:
NONE
Integrity Impact:
NONE
Availability Impact:
HIGH

Timeline

Reported to Red Hat.

Made public.

Weakness Type

NULL Pointer Dereference

A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. NULL pointer dereference issues can occur through a number of flaws, including race conditions, and simple programming omissions.


Products Associated with CVE-2026-76781

You can be notified by email with stack.watch whenever vulnerabilities like CVE-2026-76781 are published in these products:

Red Hat Enterprise Linux (RHEL)
 
Red Hat Hummingbird
 
Red Hat Openshift
 
Canonical Ubuntu Linux
 

Affected Versions

Red Hat Hardened Images: Red Hat Enterprise Linux 10: Red Hat Enterprise Linux 10: Red Hat Enterprise Linux 6: Red Hat Enterprise Linux 7: Red Hat Enterprise Linux 8: Red Hat Enterprise Linux 8: Red Hat Enterprise Linux 8: Red Hat Enterprise Linux 9: Red Hat Enterprise Linux 9: Red Hat Hardened Images: Red Hat OpenShift Container Platform 4: Red Hat OpenShift Container Platform 4: Red Hat OpenShift Container Platform 4: