CVE-2021-31805 | Forced OGNL evaluation, when evaluated on raw not validated user input in tag attributes, may lead to RCE.

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.

Published: 2022-04-12 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-31805 is rated High Risk (74/100): CVSS Critical severity, with high exploitation likelihood (EPSS 93.79%, 100th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. High exploitation likelihood—assess exposure and prioritize remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-31805

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-11 93.96% 93.79% -0.17%
2 2025-11-21 93.72% 93.96% +0.23%
3 2025-11-18 — 93.72% —

Full EPSS history (35 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-31805

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.8 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 5.9 [email protected]
7.5 2.0 HIGH
AV:N/AC:L/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 6.4 [email protected]

Weakness enumeration for CVE-2021-31805

GitHub Security Advisory for CVE-2021-31805

GHSA-v8j6-6c2r-r27c · Severity: critical · Ecosystem: maven — Expression Language Injection in Apache Struts

OS Trackers for CVE-2021-31805

vendor priority summary link
redhat high — https://access.redhat.com/security/cve/CVE-2021-31805
ubuntu medium CVE-2021-31805 medium priority: Ubuntu including 1 source packages (libstruts1.2-java), 7 status rows across 7 suites (bionic, focal, impish, jammy, trusty, upstream, xenial): DNE 6, not-affected 1. https://ubuntu.com/security/CVE-2021-31805

Affected software / configurations for CVE-2021-31805

Vendor Product Version Raw CPE
apache struts >= 2.0.0, <= 2.5.29 cpe:2.3:a:apache:struts:*:*:*:*:*:*:*:*

References for CVE-2021-31805

cvelogic Threat Intelligence