CVE-2021-28040: Ossec

High severity, CVSS 7.5. EPSS: 1.2% chance of exploitation in the next 30 days.

An issue was discovered in OSSEC 3.6.0. An uncontrolled recursion vulnerability in os_xml.c occurs when a large number of opening and closing XML tags is used. Because recursion is used in _ReadElem without restriction, an attacker can trigger a segmentation fault once unmapped memory is reached.

Affected products

• Ossec Ossec: version 3.6.0 only

Published 2021-03-05. Last modified 2026-06-17.