CVE-2016-3087 is a critical-severity (CVSS 9.8) Improper Input Validation vulnerability in org.apache.struts:struts2-core. 5 public exploit or proof-of-concept references are indexed, so weaponization risk is real. A fix is available for org.apache.struts:struts2-core — see the affected versions and patch details below.
Apache Struts vulnerable to arbitrary remote code execution due to improper input validation
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
org.apache.struts:struts2-core☕org.apache.struts:struts2-core☕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
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, allow remote attackers to execute arbitrary code via vectors related to an ! (exclamation mark) operator to the REST Plugin.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.apache.struts:struts2-core | ≥ 2.3.19&&< 2.3.20.3 | 2.3.20.3org.apache.struts:struts2-core:2.3.20.3 |
| ☕Maven | org.apache.struts:struts2-core | ≥ 2.3.21&&< 2.3.24.3 | 2.3.24.3org.apache.struts:struts2-core:2.3.24.3 |
| ☕Maven | org.apache.struts:struts2-core | ≥ 2.3.25&&< 2.3.28.1 | 2.3.28.1org.apache.struts:struts2-core:2.3.28.1 |
Affected Products
strutsapacheResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Apache Struts - REST Plugin With Dynamic Method Invocation Remote Code Execution
by nixawk · Jun 6, 2017
Apache Struts - REST Plugin With Dynamic Method Invocation Remote Code Execution (Metasploit)
by Metasploit · Jun 10, 2016
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 2.3.20.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2016-3087 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.
Frequently Asked Questions
Is CVE-2016-3087 in your dependencies?
Find it across Maven, including transitive dependencies.