Answer in brief
CVE-2026-55691 records a High severity 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.
A CVSS score is not reported in the current record. 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 | Not reported |
Published upstream
Sep 15, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 15, 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.