CVE-2026-86139: Xmlsoft LIBXML2

High severity, CVSS 7.8. EPSS: 0.2% chance of exploitation in the next 30 days.

In libxml2 before 2.15.4, xmlURIEscapeStr in uri.c has an integer overflow.

Affected products

• Xmlsoft LIBXML2: before 2.15.4 (fixed in 2.15.4)

Published 2026-09-05. Last modified 2026-09-15.