High [CVE-2025-6021] Libxml2: integer overflow in xmlbuildqname leads to stack buffer overflow in libxml2

A flaw was found in libxml2's xmlBuildQName function, where integer overflows in buffer size calculations can lead to a stack-based buffer overflow. This issue can result in memory corruption or a denial of service when processing crafted input.

This vulnerability is rated Moderate due to the lack of confidentiality impact and limited integrity concerns, with the main risk being potential denial-of-service from a crash. Exploitation requires crafted XML input and specific application behavior using xmlBuildQName.

While it’s a write overflow, modern mitigations make remote code execution unlikely. Red Hat severity: Moderate — CVSS 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

Weakness: CWE-787.

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 23 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 19 more.