CVE-2012-0391 — Apache Struts 2 Improper Input Validation Vulnerability

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

• Maven Org.apache.struts:struts2-core: fixed in version 2.2.3.1 — github.com (GitHub Security Advisories)
• Maven Org.apache.struts.xwork:xwork-core: fixed in version 2.2.3.1 — github.com (GitHub Security Advisories)

CISA required action CISA

Apply updates per vendor instructions.

US federal deadline: Jul 21, 2022 — passed 1547 day(s) ago

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

1. Identify exposed assets running the affected vendor/product/version combinations (Apache Software Foundation Struts, Maven Org.apache.struts:struts2-core, Maven Org.apache.struts.xwork:xwork-core).
2. Treat as emergency remediation: the CVE is in CISA KEV (confirmed exploitation).
3. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
4. Apply the fixed version or the patch documented under Remediation.
5. EPSS ahead of 100% of scored CVEs: prioritize it in the patch queue.
6. Search available logs for exploit probes matching the vulnerability class (injection), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-94 · Code Injection

Other CVEs with this weakness →

CISA KEV details CISA

CISA lists a CVE once it has evidence of exploitation against real targets.

CISA records ransomware use only for campaigns it has confirmed, so “Unknown” means unrecorded, not ruled out. The deadline binds US federal agencies; for everyone else it is a reference date.

Public exploits, PoCs and detection templates

Public code that demonstrates or tests the flaw raises the odds of mass exploitation — and Nuclei templates help find vulnerable assets in your environment.

Warning: public PoCs are sometimes disguised malware. Use them only for authorized testing in an isolated environment. This portal does not host exploit code — it only points to the sources.

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 75.60%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

• Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
• Look for parameters with command/query metacharacters and unexpected child processes of the service.
• Hunt retroactively in logs from before Jan 21, 2022 (KEV listing): exploitation may have started earlier.

Timeline

What happened to this CVE, newest first.

• 2026
• Fix documented
  Oct 13, 2026 · GitHub Security Advisories
• Affected products added · maven/org.apache.struts:struts2-core, maven/org.apache.struts.xwork:xwork-core
  Oct 13, 2026 · GitHub Security Advisories
• SSVC assessment updated
  Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
• Record published
  Oct 13, 2026
• Affected products added · apache/struts
  Oct 13, 2026 · NIST National Vulnerability Database
• CVSS changed · 9.8
  Oct 13, 2026 · NIST National Vulnerability Database
• Source status changed · → Analyzed
  Oct 13, 2026 · NIST National Vulnerability Database
• Added to CISA KEV (detected)
  Oct 13, 2026 · CISA Known Exploited Vulnerabilities
• Record created in this database
  Oct 13, 2026 · CISA Known Exploited Vulnerabilities
• 2022
• Added to CISA KEV catalog
  Jan 20, 2022 · CISA
• 2012
• CVE published
  Jan 8, 2012 · mitre

Source activity

Repeated readings are counted rather than listed.

• 2× References added · Oct 13, 2026 – Oct 13, 2026
• 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

13 on the record

• secunia.com/advisories/47393
  Vendor Advisory, third-party-advisory, x_refsource_SECUNIA, NIST National Vulnerability Database
• struts.apache.org/2.x/docs/s2-008.html
  Vendor Advisory, x_refsource_CONFIRM, NIST National Vulnerability Database
• struts.apache.org/2.x/docs/version-notes-2311.html
  Vendor Advisory, x_refsource_CONFIRM, NIST National Vulnerability Database
• issues.apache.org/jira/browse/WW-3668
  Vendor Advisory, x_refsource_CONFIRM, NIST National Vulnerability Database
• www.cisa.gov/known-exploited-vulnerabilities-catalog
  US Government Resource, NIST National Vulnerability Database
• github.com/apache/struts/commit/b4265d369dc29d57a9f2846a85b26598e83f3892
  GitHub Security Advisories
• archives.neohapsis.com/archives/bugtraq/2012-01/0031.html
  Broken Link, Exploit, mailing-list, x_refsource_BUGTRAQ, NIST National Vulnerability Database
• github.com/apache/struts/commit/25e50069d60434a30395e3a98357ffba2bed427e
  GitHub Security Advisories
• nvd.nist.gov/vuln/detail/CVE-2012-0391
  GitHub Security Advisories
• www.exploit-db.com/exploits/18329
  Exploit, exploit, x_refsource_EXPLOIT-DB, NIST National Vulnerability Database
• www.sec-consult.com/files/20120104-0_Apache_Struts2_Multiple_Critical_Vulnerabilities.txt
  Broken Link, Exploit, x_refsource_MISC, NIST National Vulnerability Database
• github.com/apache/struts/commit/5f54b8d087f5125d96838aafa5f64c2190e6885b
  GitHub Security Advisories
• github.com/advisories/GHSA-4wrr-9h5r-m92w
  GitHub Security Advisories

Elsewhere on this site

Related CVEs (same products)

• High CVE-2026-104714 Apache Struts: Shared message formatter exposes date and time values across concurrent requests 10d
• Critical CVE-2026-104711 Apache Struts: OGNL injection in the legacy RESTful action mapper 10d
• High CVE-2026-104712 Apache Struts: Disproportionate response size when rendering BigDecimal request parameters 10d
• Medium CVE-2026-104713 Apache Struts: Unbounded request body read in the REST plugin 10d
• Medium CVE-2026-73632 Exposure of data element to wrong session vulnerability in the JSON plugin of Apache… Aug 15, 2026
• High CVE-2026-73634 Uncontrolled Resource Consumption in Apache Software Foundation Struts Aug 15, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

• No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
• No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
• No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2012-0391 is "Apache Struts 2 Improper Input Validation Vulnerability", rated Critical. It affects Struts (Apache Software Foundation); versions are in the scope table. It is in CISA KEV: there is evidence of real-world exploitation. CVSS 9.8 describes technical severity. EPSS 75.60% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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