CVE-2026-25210: Libexpat Project Libexpat

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

In libexpat before 2.7.4, the doContent function does not properly determine the buffer size bufSize because there is no integer overflow check for tag buffer reallocation.

Affected products

• Libexpat Project Libexpat: before 2.7.4 (fixed in 2.7.4)

Published 2026-01-30. Last modified 2026-06-17.