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Mediawiki EmbedVideo Extension has stored XSS via malformed src url with $wgEmbedVideoRequireConsent disabled

High severity GitHub Reviewed Published Jun 24, 2026 in StarCitizenWiki/mediawiki-extensions-EmbedVideo

Package

composer starcitizenwiki/embedvideo (Composer)

Affected versions

<= 4.0.0

Patched versions

4.1.0

Description

Summary

With $wgEmbedVideoRequireConsent disabled (not the default), the urls for videos are passed into an iframe src attribute without sanitization. When given a malformed url or id, the src attribute can be escaped via double quotes, allowing for html/javascript injection.

Details

The iframe assembled here adds the url from getUrl() as the src without sanitization.
The id regex for the archiveorg service and the url regexes for the wistia and sharepoint services allow for double quotes to be introduced.

PoC

Using double quotes, the src attribute can be escaped.

<embedvideo service="archiveorg" id='a" onmouseover="alert(document.domain)" data-x="'></embedvideo>

Impact

When $wgEmbedVideoRequireConsent = false, any user able to edit a page can inject arbitrary JavaScript into an HTML event handler attribute (e.g. onfocus) via parameter. It requires no interaction (autofires via autofocus) and executes in the wiki origin for every visitor to the page.

References

@octfx octfx published to StarCitizenWiki/mediawiki-extensions-EmbedVideo Jun 24, 2026
Published by the National Vulnerability Database Sep 24, 2026
Published to the GitHub Advisory Database Sep 25, 2026
Reviewed Sep 25, 2026

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
None
Availability
None

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:N/A:N

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(15th percentile)

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.

Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)

The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special characters such as <, >, and & that could be interpreted as web-scripting elements when they are sent to a downstream component that processes web pages. Learn more on MITRE.

CVE ID

CVE-2026-57440

GHSA ID

GHSA-v65j-hff3-753c

Source code

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