CVE-2026-55691

EmbedVideo Extension : Stored XSS via unsanitized class passed to template

Published Sep 15, 2026 CVSS 3.1 · 8.6 High EPSS < 1% KEV · Not listed
Description
The EmbedVideo Extension is a MediaWiki extension which adds a parser function called #ev and various parser tags for embedding video clips from various video sharing services. Prior to 4.1.0, EmbedHtmlFormatter::toHtml in includes/EmbedService/EmbedHtmlFormatter.php passes the user-supplied class value directly to sprintf while constructing a figure element. A quote in the class value can terminate the class attribute and inject arbitrary HTML attributes or markup into the rendered page. A user able to edit a wiki page can store JavaScript that executes for visitors who render the affected content. This issue is fixed in version 4.1.0.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-7h5p-637f-jfr7 StarCitizenWiki Extension Embed Video: Stored XSS via unsanitized class passed to template
History
Type Values Removed Values Added
First Time appeared Starcitizenwiki
Starcitizenwiki mediawiki-extensions-embedvideo
Vendors & Products Starcitizenwiki
Starcitizenwiki mediawiki-extensions-embedvideo
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description The EmbedVideo Extension is a MediaWiki extension which adds a parser function called #ev and various parser tags for embedding video clips from various video sharing services. Prior to 4.1.0, EmbedHtmlFormatter::toHtml in includes/EmbedService/EmbedHtmlFormatter.php passes the user-supplied class value directly to sprintf while constructing a figure element. A quote in the class value can terminate the class attribute and inject arbitrary HTML attributes or markup into the rendered page. A user able to edit a wiki page can store JavaScript that executes for visitors who render the affected content. This issue is fixed in version 4.1.0.
Title EmbedVideo Extension : Stored XSS via unsanitized class passed to template
Weaknesses CWE-79
References
Metrics cvssV3_1

{'score': 8.6, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Sep 16, 2026, 3:44 PM
Reserved
Jun 17, 2026, 12:13 AM
Status
Deferred
Published
Sep 15, 2026, 5:17 PM
Modified
Sep 30, 2026, 5:51 PM