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Vulnerability · Published Sep 15, 2026 · Assigned by GitHub_M

CVE-2026-55691EmbedVideo Extension : Stored XSS via unsanitized class passed to template

High 8.6

In plain English

A high-severity cross-site scripting in mediawiki-extensions-EmbedVideo from StarCitizenWiki. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 42% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.6High
Exploit odds (30 days)0.5%top 58.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Packagiststarcitizenwiki/embedvideo4.1.0GHSA-7h5p-637f-jfr7

Affected products (as reported)

VendorProductVersions
StarCitizenWiki mediawiki-extensions-EmbedVideo < 4.1.0

Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L

References