XSS in Starcitizenwiki Mediawiki-Extensions-Embedvideo
CVE-2026-55690
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.
Vulnerability class: XSS (Cross-Site Scripting)
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.
Affected products
- Starcitizenwiki Mediawiki-extensions-embedvideo — versions < 4.1.0
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
Frequently asked questions
- What is CVE-2026-55690?
- CVE-2026-55690 is a high-severity vulnerability in Starcitizenwiki Mediawiki-Extensions-Embedvideo, classified under Cross-site Scripting. CVSS score: 7.5/10. Published 2026-09-15.
- How severe is CVE-2026-55690?
- High severity. CVSS v3 base score is 7.5 out of 10.