libxml2 Uncontrolled Recursion Vulnerability in xmlcatalog Component

A vulnerability allowing uncontrolled recursion has been identified in libxml2 versions through 2.14.5. This issue arises in the xmlcatalog component, specifically within the xmlParseSGMLCatalog function. The vulnerability can be triggered by processing untrusted SGML catalogs, leading to excessive resource consumption and application crashes. Although an exploit is publicly available, the existence of this vulnerability is currently disputed.

Impact

Exploitation of this vulnerability causes a stack overflow, leading to a crash of the application.

Reproduction

The vulnerability can be reproduced by using the xmlcatalog tool with the '--sgml --shell --create --add' options, along with a crafted SGML catalog file that exploits the recursion issue. This causes the xmlExpandCatalog and xmlParseSGMLCatalog functions to call each other repeatedly, without termination, until the stack memory is exhausted, resulting in a crash.