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Star Citizen EmbedVideo Extension Stored XSS through wikitext caused by usage of non-reserved data attributes

High severity GitHub Reviewed Published Sep 24, 2025 in StarCitizenWiki/mediawiki-extensions-EmbedVideo • Updated Sep 24, 2025

Package

composer starcitizenwiki/embedvideo (Composer)

Affected versions

<= 4.0.0

Patched versions

None

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

  1. Create a page with the following contents:
<div class="embedvideo-evl" data-iframeconfig='{"onload": "alert(1)"}'>Click me!</div>
<evlplayer></evlplayer>
  1. Click on the "Click me!" text
  2. Click on the "Load video" button below

image

Impact

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

References

@octfx octfx published to StarCitizenWiki/mediawiki-extensions-EmbedVideo Sep 24, 2025
Published to the GitHub Advisory Database Sep 24, 2025
Reviewed Sep 24, 2025
Last updated Sep 24, 2025

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
Low
Availability
Low

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L

EPSS score

Weaknesses

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. Learn more on MITRE.

CVE ID

CVE-2025-59839

GHSA ID

GHSA-4j5h-mvj3-m48v

Source code

Credits

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