CVE-2015-5209 — struts2-core
HIGHCVE-2015-5209 is a high-severity (CVSS 7.5) Improper Input Validation vulnerability in org.apache.struts:struts2-core. A fix is available for org.apache.struts:struts2-core — see the affected versions and patch details below.
Special top object can be used to access Struts' internals
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-2015-5209 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,166 CVEs with a current EPSS score, this one falls in the < 10% 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
ValueStack defines special top object which represents root of execution context. It can be used to manipulate Struts' internals or can be used to affect container's settings. Applying better regex which includes pattern to exclude request parameters trying to use top object. This issue was patched in Struts 2.3.24.1.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.apache.struts:struts2-core | all versions | 2.3.24.1org.apache.struts:struts2-core:2.3.24.1 |
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 2.3.24.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2015-5209 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-2015-5209 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2015-5209. 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-2015-5209 in your dependencies?
O3 Security finds CVE-2015-5209 across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.