Executive brief
libxml2 is a widely-used XML parsing library embedded in many applications and system tools. A specially crafted XML catalog file can crash applications using libxml2 when they attempt to parse it, causing a denial of service that disrupts normal operations. This can be exploited by a local user or by providing a malicious XML file to any application that processes catalogs.
Technical details
A NULL pointer dereference vulnerability exists in libxml2's XML catalog parsing logic. The flaw occurs when a `nextCatalog` element in an XML catalog is missing its mandatory `catalog` attribute—the parser fails to validate this precondition and attempts to dereference a NULL pointer, causing the application to crash. The attack vector is local or network-based (if the application accepts untrusted XML catalog input), requires no authentication or special privileges, and results in denial of service. Patch availability has not been confirmed from the provided information.
Affected products
- libxml2 project libxml2
Timeline
- 2026-09-17: disclosed