GHSA-wmq2-jc9m-xp4m — jruby-core
GHSA-wmq2-jc9m-xp4m is a Cross-site Scripting (XSS) vulnerability in org.jruby:jruby-core. 1 public exploit reference exists, so weaponization risk is real. A fix is available for org.jruby:jruby-core — see the affected versions and patch details below.
Cross-site Scripting in in JRuby
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.
Real-World Exposure
org.jruby:jruby-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
The regular expression engine in JRuby before 1.4.1, when $KCODE is set to 'u', does not properly handle characters immediately after a UTF-8 character, which allows remote attackers to conduct cross-site scripting (XSS) attacks via a crafted string.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.jruby:jruby-core | all versions | 1.4.1org.jruby:jruby-core:1.4.1 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.jruby:jruby-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.jruby:jruby-core to 1.4.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-wmq2-jc9m-xp4m 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-wmq2-jc9m-xp4m can be triaged on real exposure rather than presence alone.
Tailored to GHSA-wmq2-jc9m-xp4m. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Frequently Asked Questions
Is GHSA-wmq2-jc9m-xp4m in your dependencies?
O3 Security finds GHSA-wmq2-jc9m-xp4m across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.