Uncontrolled recursion vulnerability in the xmlCatalogXMLResolveURI function of the libxml2 XML parsing library. The issue occurs when an XML catalog contains a delegate URI entry that references the catalog itself. During entity resolution, the function recursively resolves the same catalog entry without detecting the cyclic reference. This results in infinite recursion and eventual call stack exhaustion, leading to a segmentation fault. Exploitation is configuration-dependent and primarily impacts availability by allowing an attacker to crash affected applications.