Executive Summary

A use‑after‑free flaw in libxml2 triggers when parsing XPath elements that reference in an XML Schematron. A crafted XML document can cause the library to crash or exhibit undefined behavior, potentially leading to denial‑of‑service or other exploitation vectors. The vulnerability is not yet listed in CISA KEV.

---

Authoritative CVE Metadata - CVSS Base Score: 9.1 (CRITICAL) - Published: 2025-06-16T16:15:18.997 - Last Modified: 2026-09-28T02:17:15.060

Original Description: A use-after-free vulnerability was found in libxml2. This issue occurs when parsing XPath elements under certain circumstances when the XML schematron has the schema elements. This flaw allows a malicious actor to craft a malicious XML document used as input for libxml, resulting in the program's crash using libxml or other possible undefined behaviors.

"This is the final test of a gentleman: his respect for those who can be of no possible value to him."

— William Lyon Phelps