GHSA-fc46-r95f-hq7g
HIGHGHSA-fc46-r95f-hq7g is a high-severity (CVSS 8.7) Cross-site Scripting (XSS) vulnerability in decidim-core. O3 Security confirms whether GHSA-fc46-r95f-hq7g is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Decidim has a cross-site scripting (XSS) in user name
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-fc46-r95f-hq7g 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 356,530 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
decidim-core💎decidim-coreReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.
Description
Impact
A stored code execution vulnerability in the user name field allows a low-privileged attacker to execute arbitrary code in the context of any user who passively visits a comment page, resulting in high confidentiality and integrity impact across security boundaries.
Patches
N/A
Workarounds
Not available
References
OWASP ASVS v4.0.3-5.1.3
Credits
This issue was discovered in a security audit organized by octree and made by Secu Labs against Decidim financed by the city of Lausanne (Switzerland).
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | decidim-core | ≥ 0.31.0.rc1&&< 0.31.1 | 0.31.1 |
| 💎RubyGems | decidim-core | all versions | 0.30.5 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for decidim-core. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update decidim-core to 0.31.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-fc46-r95f-hq7g 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 pinpoints whether GHSA-fc46-r95f-hq7g is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-fc46-r95f-hq7g. 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-fc46-r95f-hq7g in your dependencies?
O3 detects GHSA-fc46-r95f-hq7g across RubyGems dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.