Summary
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.
Impact
Untrusted input is evaluated as executable code within the application's runtime environment. Typical impact: arbitrary code execution within the application's privilege context.
CVE-2011-3923 has a CVSS score of 9.8 (Critical). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (2.3.1.2); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Remediation advice
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2011-3923? CVE-2011-3923 is a critical-severity code injection vulnerability in org.apache.struts:struts2-core (maven), affecting versions >= 2.0.0, < 2.3.1.2. It is fixed in 2.3.1.2. Untrusted input is evaluated as executable code within the application's runtime environment.
- How severe is CVE-2011-3923? CVE-2011-3923 has a CVSS score of 9.8 (Critical). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of org.apache.struts:struts2-core are affected by CVE-2011-3923? org.apache.struts:struts2-core (maven) versions >= 2.0.0, < 2.3.1.2 is affected.
- Is there a fix for CVE-2011-3923? Yes. CVE-2011-3923 is fixed in 2.3.1.2. Upgrade to this version or later.
- Is CVE-2011-3923 exploitable, and should I be worried? Whether CVE-2011-3923 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2011-3923 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2011-3923? Upgrade
org.apache.struts:struts2-coreto 2.3.1.2 or later.