CVE-2025-53370

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

1. Enable Citizen and ShortDescription
2. Add {{SHORTDESC:<img src="" onerror="alert('citizen shortdescription xss')">}} to a page
3. Visit the page
   
   

Arbitrary HTML can be inserted into the DOM by any user, allowing for JavaScript to be executed.

Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.

CVE-2025-53370 has a CVSS score of 8.6 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (3.4.0); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2025-53370? CVE-2025-53370 is a high-severity cross-site scripting (XSS) vulnerability in starcitizentools/citizen-skin (composer), affecting versions >= 1.9.4, < 3.4.0. It is fixed in 3.4.0. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
2. How severe is CVE-2025-53370? CVE-2025-53370 has a CVSS score of 8.6 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of starcitizentools/citizen-skin are affected by CVE-2025-53370? starcitizentools/citizen-skin (composer) versions >= 1.9.4, < 3.4.0 is affected.
4. Is there a fix for CVE-2025-53370? Yes. CVE-2025-53370 is fixed in 3.4.0. Upgrade to this version or later.
5. Is CVE-2025-53370 exploitable, and should I be worried? Whether CVE-2025-53370 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2025-53370 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2025-53370? Upgrade starcitizentools/citizen-skin to 3.4.0 or later.