CVE-2021-31805

Forced OGNL evaluation, when evaluated on raw not validated user input in tag attributes, may lead to RCE.

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.

Remediation

Workaround:

  • Avoid using forced OGNL evaluation on untrusted user input, and/or upgrade to Struts 2.5.30 which checks if expression evaluation won’t lead to the double evaluation. Please read our Security Bulletin S2-062 for more details.

Category

9.8
CVSS
Severity: Critical
CVSS 3.1 •
CVSS 2.0 •
EPSS 93.92% Top 5%
Vendor Advisory apache.org
Affected: Apache Software Foundation Apache Struts
Published at:
Updated at:

References

Link Tags
https://cwiki.apache.org/confluence/display/WW/S2-062 patch vendor advisory mitigation
http://www.openwall.com/lists/oss-security/2022/04/12/6 mailing list third party advisory mitigation
https://www.oracle.com/security-alerts/cpujul2022.html
https://security.netapp.com/advisory/ntap-20220420-0001/ third party advisory

Frequently Asked Questions

What is the severity of CVE-2021-31805?
CVE-2021-31805 has been scored as a critical severity vulnerability.
How to fix CVE-2021-31805?
As a workaround for remediating CVE-2021-31805: Avoid using forced OGNL evaluation on untrusted user input, and/or upgrade to Struts 2.5.30 which checks if expression evaluation won’t lead to the double evaluation. Please read our Security Bulletin S2-062 for more details.
Is CVE-2021-31805 being actively exploited in the wild?
It is possible that CVE-2021-31805 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~94% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-31805?
CVE-2021-31805 affects Apache Software Foundation Apache Struts.
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