Threats / Apache / CVE-2012-0391
CVE-2012-0391
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-08-04
Apache Struts 2 vulnerability
Apache Struts 2 before 2.2.3.1 contains an improper input validation flaw in the ExceptionDelegator component that enables remote code execution.
Verdict
Today item — known-exploited.
The vulnerability allows unauthenticated attackers to execute arbitrary code on affected systems through crafted input. With an EPSS score of 0.875 and confirmed exploitation in the wild, this represents a critical risk requiring immediate patching.
CISA KEV Yes · 2022-01-214EPSS 0.75071 (verify live)5CVSS 9.8 (CISA)3CISA SSVC Exploitation: active · Automatable: yes · Impact: total3Exploit Weaponized · public exploit · Metasploit module9
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
2 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2022-01-21).
Probability (EPSS)
EPSS 0.75071 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
CVSS 9.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H) · Affected: Apache, Struts 2. Confirm exact fixed builds in the vendor advisory.CVSS — CISA-assigned via the ADP container (CVE.org), version 3.1; the CNA left no metrics, so CISA's own score is used ahead of NVD.
Weakness (CWE)
Mapped to CWE-20 Improper Input Validation.CWE assignment from the public NVD record (may be stale); the weakness class drives how the flaw is exploited.
CISA SSVC (triage disposition)
Exploitation: active · Automatable: yes · Technical Impact: totalCISA's own stakeholder-specific triage inputs, published in the CVE record (CISA Coordinator role). NOTE: this is CISA's three decision points; the final Act/Attend/Track decision also requires a Mission & Well-being input not published here, so no overall decision is asserted.
Currency of the record
CISA added this to its KEV catalog 3666 days after the CVE record was published.KEV lag = CISA-KEV dateAdded − CVE.org datePublished; a floor on how long the known-exploited flaw sat in the public record before the federal catalog listed it. Severity/weakness here is CNA- or CISA-assigned (current at disclosure), independent of NVD's analysis backlog.
Public exploit available
Public exploit tooling is catalogued for this CVE (a functional/weaponized public exploit). Catalog entries: Metasploit module. We link the catalog page(s) only — no payload or code is hosted or restated here.Link, never host — the catalog page is the source; basicsecurity.net does not redistribute payloads.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I craft malicious input that bypasses validation in the ExceptionDelegator component.
Business
Attackers gain the ability to execute arbitrary code with application privileges on internet-facing web servers.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I deliver the payload through standard HTTP requests to vulnerable Struts 2 applications.
Business
No authentication or special access is required, making the attack surface extremely broad across all exposed instances.
3
Lateral reach — past segmentation narrative 3
Attacker
I establish command execution and pivot to internal systems or exfiltrate sensitive data.
Business
Complete compromise of web application infrastructure, potential lateral movement, and data breach impact across dependent systems.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05