Critical [CVE-2025-49794] heap use after free (uaf) leads to denial of service (dos)

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 issue was rated with a severity impact of Important by Red Hat Product Security, as libxml can be used to parse XML coming from the network depending on how the program consumes it and uses the library.

Additionally, although the initial report shows a crash due to invalid memory access (A:H), other undefined issues that can present data integrity due to the application overwriting sensitive data are not discarded (I:H). Weakness: CWE-825.

Affected products named by the advisory: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 7 Extended Lifecycle Support; Red Hat Enterprise Linux 8.2 Advanced Update Support; Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support; and 26 more.

Affected products named by the advisory: Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On; Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support; Red Hat Enterprise Linux 8.6 Telecommunications Update Service; Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions; and 22 more.