CVE-2021-31805Public exploitNetwork attack vector

Remote code execution via double-evaluated OGNL input

Published Apr 12, 2022 · Updated Aug 3, 2024

Expression language injection in Apache Struts 2.0.0 through 2.5.29 allows remote attackers to execute arbitrary code via crafted input. Affected tag attributes evaluate forced %{...} OGNL syntax, then treat the resulting untrusted string as a second OGNL expression. A Struts application is exposed only when its developer applies forced OGNL evaluation to a tag attribute fed by raw, unvalidated user input; successful exploitation runs code in the application process.

CVSS severity9.8
Critical
EPSS probability85.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Expression language injection in Apache Struts 2.0.0 through 2.5.29 allows remote attackers to execute arbitrary code via crafted input. Affected tag attributes evaluate forced %{...} OGNL syntax, then treat the resulting untrusted string as a second OGNL expression. A Struts application is exposed only when its developer applies forced OGNL evaluation to a tag attribute fed by raw, unvalidated user input; successful exploitation runs code in the application process.

The record

CVE
CVE-2021-31805
Published
Apr 12, 2022
Updated
Aug 3, 2024
Vendor
The Apache Software Foundation
Product
Apache Struts
Classifications
CWE-917, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 12, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.0.0 to 2.5.29

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache Strutsversion=2.0.0 to 2.5.29

Published CVSS scores

9.8NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-917Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection')
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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