GHSA-m3x6-9v6h-4g28 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in org.apache.struts:struts2-core. EPSS puts its 30-day exploitation probability at 11.6% (96th percentile). A fix is available for org.apache.struts:struts2-core — see the affected versions and patch details below.
Cross-site Scripting in Apache Struts
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
GHSA-m3x6-9v6h-4g28 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 10–50% 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
Cross-site scripting (XSS) vulnerability in the URLDecoder function in JRE before 1.8, as used in Apache Struts 2.x before 2.3.28, when using a single byte page encoding, allows remote attackers to inject arbitrary web script or HTML via multi-byte characters in a url-encoded parameter.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.apache.struts:struts2-core | ≥ 2.0.0&&< 2.3.28 | 2.3.28org.apache.struts:struts2-core:2.3.28 |
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 2.3.28 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-m3x6-9v6h-4g28 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 GHSA-m3x6-9v6h-4g28 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-m3x6-9v6h-4g28. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-m3x6-9v6h-4g28 in your dependencies?
O3 Security finds GHSA-m3x6-9v6h-4g28 across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.