CVE-2025-53370 — starcitizentools/citizen-…
HIGHFix: StarCitizenTools/mediawiki-skins-Citizen@c85a40bCVE-2025-53370 is a high-severity (CVSS 8.6) Cross-site Scripting (XSS) vulnerability in starcitizentools/citizen-skin. A fix is available for starcitizentools/citizen-skin — see the affected versions and patch details below.
Citizen stored XSS vulnerability through short descriptions
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-53370.
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-2025-53370 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 378,156 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
starcitizentools/citizen-skinReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
Summary
Short descriptions set via the ShortDescription extension are inserted as raw HTML by the Citizen skin, allowing any user to insert arbitrary HTML into the DOM by editing a page.
Details
The shortdesc property, which contains unsanitized user input, is retrieved from the OutputPage and returned as the tagline:
https://github.com/StarCitizenTools/mediawiki-skins-Citizen/blob/0d8a44011e02a081618359a1e90f462478e807aa/includes/Components/CitizenComponentPageHeading.php#L249-L251
The tagline is then provided to the template data:
https://github.com/StarCitizenTools/mediawiki-skins-Citizen/blob/0d8a44011e02a081618359a1e90f462478e807aa/includes/Components/CitizenComponentPageHeading.php#L270-L275
The template then inserts the tagline into raw HTML without doing any escaping:
https://github.com/StarCitizenTools/mediawiki-skins-Citizen/blob/0d8a44011e02a081618359a1e90f462478e807aa/templates/PageHeading.mustache#L12
PoC
- Enable Citizen and ShortDescription
- Add
{{SHORTDESC:<img src="" onerror="alert('citizen shortdescription xss')">}}to a page - Visit the page
Impact
Arbitrary HTML can be inserted into the DOM by any user, allowing for JavaScript to be executed.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | starcitizentools/citizen-skin | ≥ 1.9.4&&< 3.4.0 | 3.4.0composer require starcitizentools/citizen-skin:^3.4.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for starcitizentools/citizen-skin, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update starcitizentools/citizen-skin to 3.4.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-53370 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-2025-53370 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2025-53370. 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-2025-53370 in your dependencies?
O3 Security finds CVE-2025-53370 across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.