Apache Struts 1 Improper Input Validation Vulnerability
The Struts 1 plugin in Apache Struts 2.1.x and 2.3.x might allow remote code execution via a malicious field value passed in a raw message to the ActionMessage.
Severity = CVSS. Probability = EPSS (FIRST). Exploitation = public signals: KEV, EUVD, ransomware, EPSS above 10 %, no account required.
Exploitation probability EPSS · FIRST
Exploitation signals 4 / 5
- KEV catalog (CISA)10 Feb 2022
- Exploited in EUVD (ENISA)10 Feb 2022
- Used by ransomwareno
- EPSS above 10 %98.9%
- No account, over the networkyes
What to do
Fix
Apply the vendor’s fix as soon as it is available.
CISA guidance: Apply updates per vendor instructions.
Meanwhile
Take the service off the internet or restrict access to it, watch the logs and look for signs of compromise.
Manufacturers (CRA)
Exploited vulnerability in your product: early warning to ENISA within 24 h, then notification within 72 h (Article 14 of the Cyber Resilience Act). The CRA explained
Affected products
- 2.3.x series
- 2.1.x series
Open source packages OSV
Affected libraries according to OSV, with fixed versions.
Timeline
-
Published
-
Exploitation reported (ENISA)
-
Added to the KEV catalog
-
CISA remediation due date
-
EPSS peak: 98.9%
References
Other exploited vulnerabilities from the same vendor
- CVE-2016-3081Apache Struts Command Injection Vulnerability8.5 · Rising fast
- CVE-2026-34486Apache Tomcat Missing Encryption of Sensitive Data Vulnerability8.4 · Actively exploited
- CVE-2026-34197Apache ActiveMQ Improper Input Validation Vulnerability8.3 · Background exploitation
- CVE-2024-38475Apache HTTP Server Improper Escaping of Output Vulnerability9.0 · Background exploitation
- CVE-2025-24813Apache Tomcat Path Equivalence Vulnerability9.4 · Background exploitation
- CVE-2024-45195Apache OFBiz Forced Browsing Vulnerability9.3 · Background exploitation