Answer in brief
CVE-2026-55691 records a High severity (CVSS 8.6) vulnerability in EmbedVideo Extension : Stored XSS via unsanitized class passed to template. The current sources do not mark it as known exploited. The current feed maps starcitizenwiki/embedvideo (composer), StarCitizenWiki/mediawiki-extensions-EmbedVideo (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 8.6. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps starcitizenwiki/embedvideo (composer), StarCitizenWiki/mediawiki-extensions-EmbedVideo (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| starcitizenwiki/embedvideocomposer | <=4.0.0 | 4.1.0 |
| StarCitizenWiki/mediawiki-extensions-EmbedVideogeneric | <4.1.0 | 4.1.0 |
Published upstream
Sep 15, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 13, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jun 19, 2026
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.
Quoted source text, attributed separately from HOL analysis.