CVE-2011-3923 — struts2-core
CRITICALCVE-2011-3923 is a critical-severity (CVSS 9.8) CWE-732 vulnerability in org.apache.struts:struts2-core. 4 public exploit references exist, so weaponization risk is real. A fix is available for org.apache.struts:struts2-core — see the affected versions and patch details below.
Struts ParameterInterceptor vulnerability allows remote command execution
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2011-3923 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE sits: patch-first territory.
Where this sits among everything scored
Of 377,166 CVEs with a current EPSS score, this one falls in the 50–90% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
org.apache.struts:struts2-coreReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
Regular expression in ParametersInterceptor matches top['foo'](0) as a valid expression, which OGNL treats as (top['foo'])(0) and evaluates the value of 'foo' action parameter as an OGNL expression. This lets malicious users put arbitrary OGNL statements into any String variable exposed by an action and have it evaluated as an OGNL expression and since OGNL statement is in HTTP parameter value attacker can use blacklisted characters (e.g. #) to disable method execution and execute arbitrary methods, bypassing the ParametersInterceptor and OGNL library protections.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.apache.struts:struts2-core | ≥ 2.0.0&&< 2.3.1.2 | 2.3.1.2org.apache.struts:struts2-core:2.3.1.2 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Apache Struts - 'ParametersInterceptor' Remote Code Execution (Metasploit)
by Metasploit · Mar 22, 2013
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.struts:struts2-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.apache.struts:struts2-core to 2.3.1.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2011-3923 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2011-3923 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2011-3923. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2011-3923 in your dependencies?
O3 Security finds CVE-2011-3923 across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.