Known exploited · Apache

CVE-2020-17530: Apache Struts Remote Code Execution Vulnerability

What it is

Forced Object-Graph Navigation Language (OGNL) evaluation in Apache Struts, when evaluated on raw user input in tag attributes, can lead to remote code execution.

Added November 3, 2021Due May 3, 2022CISA KEV catalog 2026.10.01

Vendor: Apache
Product: Struts
Added to KEV: November 3, 2021
CISA due date: May 3, 2022
Ransomware use: Unknown
Weakness: CWE-917: Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection')

What CISA requires

Apply updates per vendor instructions.

Forensic triage

What to do now

Find every instance of Struts you run, including the forgotten ones, and check its version against the vendor advisory.
Apply the vendor's fix or mitigation, before May 3, 2022 if you are bound by CISA's deadline, sooner if it faces the internet.
Assume it was tried against you already: look for signs of exploitation from the date it was added, not from the day you patched.
Until every instance is patched, block the attack at the edge: a WAF in blocking mode stops Log4Shell (JNDI lookup) payloads.

References

https://nvd.nist.gov/vuln/detail/CVE-2020-17530

CVE-2020-17530 in the National Vulnerability Database

The Dome

Block it at the edge while you patch

The Dome's WAF runs the OWASP Core Rule Set in blocking mode and stops Log4Shell (JNDI lookup) payloads before they reach your application.

See the Dome

T Academy

Train the engineers who fix it

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Source: CISA Known Exploited Vulnerabilities Catalog (public domain), catalog version 2026.10.01.