CVE-2025-59839 is a high-severity (CVSS 8.6) Cross-site Scripting (XSS) vulnerability in starcitizenwiki/embedvideo. The records list no fixed version yet; check the vendor advisory below and apply the mitigations in the meantime.
Star Citizen EmbedVideo Extension Stored XSS through wikitext caused by usage of non-reserved data attributes
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-2025-59839.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
starcitizenwiki/embedvideoReal-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
The EmbedVideo extension allows adding arbitrary attributes to an HTML element, allowing for stored XSS through wikitext.
Details
The attributes of an iframe are populated with the value of an unreserved data attribute (data-iframeconfig) that can be set via wikitext:
https://github.com/StarCitizenWiki/mediawiki-extensions-EmbedVideo/blob/440fb331a84b2050f4cc084c1d31d58a1d1c202d/resources/ext.embedVideo.videolink.js#L5-L20
Similar code is also present here:
https://github.com/StarCitizenWiki/mediawiki-extensions-EmbedVideo/blob/440fb331a84b2050f4cc084c1d31d58a1d1c202d/resources/modules/iframe.js#L139-L155
It is possible to execute JS through attributes like onload or onmouseenter.
PoC
- Create a page with the following contents:
<div class="embedvideo-evl" data-iframeconfig='{"onload": "alert(1)"}'>Click me!</div>
<evlplayer></evlplayer>
- Click on the "Click me!" text
- Click on the "Load video" button below <img width="855" height="404" alt="image" src="https://github.com/user-attachments/assets/afb3839a-012c-4e90-a208-a6137b704ccd" />
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 | starcitizenwiki/embedvideo | all versions | No fix |
Affected Products
embedvideostar-citizenDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for starcitizenwiki/embedvideo, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
The records we use list no patched version of starcitizenwiki/embedvideo for CVE-2025-59839. Check the maintainer's advisory, and where your build allows, override or pin the dependency away from the vulnerable range.
Mitigate without a patch
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 CVE-2025-59839 in your dependencies?
Find it across Packagist, including transitive dependencies.