CVE-2026-55690
highpriority · track · 0EPSS 0.005 · 42 %ileUSEPSS · scored 2026-10-28
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, EmbedServiceFactory::newFromName in includes/EmbedService/EmbedServiceFactory.php interpolates an attacker-controlled unknown service name into exception text, and includes/EmbedVideo.php returns that text as HTML through the isHtml output path without neutralization. Both the #ev parser function and the evl parser form can reach this error path. A user able to edit a wiki page can inject stored HTML or JavaScript into the error output, causing code to execute in the wiki origin for visitors who render the page. This issue is fixed in version 4.1.0.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.9–7.5
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (1)
Products and version ranges known to be affected.
advisories (1)
Vendor and ecosystem advisories describing this.
- GHSA-c29q-5xm7-5p62StarCitizenWiki Extension Embed Video: Stored XSS via unsanitized service name in exception text2026-06-19ghsa · osvUS
### Summary When passing an unknown service name to embedvideo, an error message is rendered containing the invalid service name. The service name is not sanitized and can contain HTML. ### Details There is a hardcoded list of allowed services in a switch statement inside `EmbedServiceFactory#newFromName` [here](https://github.com/StarCitizenWiki/mediawiki-extensions-EmbedVideo/blob/a573a16d925ee0ea0d34b360856dc8ab0b88f822/includes/EmbedService/EmbedServiceFactory.php#L105). When the service name is not known, an exception is thrown with the service name injected into the message via sprintf [here](https://github.com/StarCitizenWiki/mediawiki-extensions-EmbedVideo/blob/a573a16d925ee0ea0d34b360856dc8ab0b88f822/includes/EmbedService/EmbedServiceFactory.php#L286). This message is not sanitized and is marked as isHtml [here](https://github.com/StarCitizenWiki/mediawiki-extensions-EmbedVideo/blob/a573a16d925ee0ea0d34b360856dc8ab0b88f822/includes/EmbedVideo.php#L303-L311). Similarly with `{{evl:` [here](https://github.com/StarCitizenWiki/mediawiki-extensions-EmbedVideo/blob/a573a16d925ee0ea0d34b360856dc8ab0b88f822/includes/EmbedVideo.php#L177-L183). ### PoC ``` // Must be on a page, not on ExpandTemplates {{#ev:<img src=x onerror=alert(document.domain)>|dQw4w9WgXcQ}} {{#evl:id=dummy|service=<img src=x onerror=alert(document.domain)>}} ``` ### Impact Stored XSS that allows arbitrary Javascript/HTML insertion on any page that a user can edit. It requires no interaction and executes in the wiki origin for every visitor to the page.
sources
Which sources assert this record, and when.
references (3) nvd
External citations — patches, advisories, analysis.
- https://github.com/StarCitizenWiki/mediawiki-extensions-EmbedVideo/commit/9215564bf28a0ceb40be550a55ab78efc0accc56
- https://github.com/StarCitizenWiki/mediawiki-extensions-EmbedVideo/releases/tag/v4.1.0
- https://github.com/StarCitizenWiki/mediawiki-extensions-EmbedVideo/security/advisories/GHSA-c29q-5xm7-5p62
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