CVE-2021-31805: apache software foundation apache struts Expression Language Injection

Vulnerability summary

CVE-2021-31805 is a critical (CVSS 9.8) Expression Language Injection vulnerability in apache software foundation apache struts. EPSS estimates a 85.43% chance of exploitation in the next 30 days, higher than 99.7% of scored vulnerabilities.

Timeline

1. 12-04-2022
   PublishedVulnerability first disclosed.
2. 03-08-2024
   Last modifiedVulnerability information updated.

Description

The fix issued for CVE-2020-17530 was incomplete. So from Apache Struts 2.0.0 to 2.5.29, still some of the tag’s attributes could perform a double evaluation if a developer applied forced OGNL evaluation by using the %{...} syntax. Using forced OGNL evaluation on untrusted user input can lead to a Remote Code Execution and security degradation.

• CWE-917Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection')The product constructs all or part of an expression language (EL) statement in a framework such as a Java Server Page (JSP) using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended EL statement before it is executed.