CVE-2012-0391: Apache Struts 2 Improper Input Validation Vulnerability

Critical severity, CVSS 9.8. Actively exploited: in CISA KEV since 2022-01-21. EPSS: 75.6% chance of exploitation in the next 30 days.

The ExceptionDelegator component in Apache Struts before 2.2.3.1 interprets parameter values as OGNL expressions during certain exception handling for mismatched data types of properties, which allows remote attackers to execute arbitrary Java code via a crafted parameter.

Affected products

• Apache Struts: before 2.2.3.1 (fixed in 2.2.3.1)

Published 2012-01-08. Last modified 2026-06-16.