RCE in Apache Struts
CVE-2021-31805
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.
Vulnerability class: Log4Shell (CVE-2021-44228)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.854 (99.7th percentile), scored .
High probability of exploitation in the next 30 days — patch promptly. 100th percentile — 99.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.854 · newest: 0.854 · change: 0.000
Affected products
- Apache Struts
- Apache Software Foundation Struts — versions 2.0.0 to 2.5.29
Weakness classification (CWE)
Public proof-of-concept exploits
References
- cwiki.apache.org/confluence/display/WW/S2-062 (Patch, Mitigation, Vendor Advisory)
- www.openwall.com/lists/oss-security/2022/04/12/6 (mailing-list, Mailing List, Third Party Advisory, Mitigation)
- www.oracle.com/security-alerts/cpujul2022.html
- security.netapp.com/advisory/ntap-20220420-0001/ (Third Party Advisory)
Frequently asked questions
- What is CVE-2021-31805?
- CVE-2021-31805 is a critical-severity vulnerability in Apache Struts, classified under Improper Neutralization of Special Elements used in an Expression Language Statement (Expression Language Injection). CVSS score: 9.8/10. Published 2022-04-12.
- How severe is CVE-2021-31805?
- Critical severity. CVSS v3 base score is 9.8 out of 10.
- Is CVE-2021-31805 known to be exploited?
- 46 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.