GHSA-fc46-r95f-hq7g — decidim-core
HIGHGHSA-fc46-r95f-hq7g is a high-severity (CVSS 8.7) Cross-site Scripting (XSS) vulnerability in decidim-core. A fix is available for decidim-core — see the affected versions and patch details below.
Decidim has a cross-site scripting (XSS) in user name
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-fc46-r95f-hq7g.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
GHSA-fc46-r95f-hq7g by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 379,842 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
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 | 0.31.1bundle update decidim-core --conservative |
| 💎RubyGems | decidim-core | all versions | 0.30.5bundle update decidim-core --conservative |
Affected Products
decidimdecidimDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for decidim-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.
Frequently Asked Questions
Is GHSA-fc46-r95f-hq7g in your dependencies?
Find it across RubyGems, including transitive dependencies.