# CVE-2026-57440: MediaWiki EmbedVideo Extension stored XSS via unescaped iframe src

Source: https://junglewise.ai/threats/cve-2026-57440-mediawiki-embedvideo-extension-stored-xss-via-unescaped-iframe  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-24. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-57440 · Severity: high · CVSS 7.5 · Published 2026-09-24

The EmbedVideo extension for MediaWiki allows wiki editors to embed videos on pages. When a specific configuration option is disabled, the extension fails to sanitize user-supplied video identifiers before inserting them into HTML iframe elements, allowing attackers to inject arbitrary JavaScript code that executes for all page visitors without requiring any user interaction.

Technologies: [starcitizenwiki/embedvideo (Packagist)](https://junglewise.ai/threats/technologies/starcitizenwiki-embedvideo), [StarCitizenWiki EmbedVideo](https://junglewise.ai/threats/technologies/embedvideo). Vendors: [Packagist](https://junglewise.ai/threats/vendors/packagist), [StarCitizenWiki](https://junglewise.ai/threats/vendors/starcitizenwiki).

## Quick answers

**Is CVE-2026-57440 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-57440 being exploited in the wild.

**How severe is CVE-2026-57440?** High severity, with a CVSS score of 7.5, published 24 September 2026.

**Which products and versions are affected?** starcitizenwiki/embedvideo (Packagist) <= 4.0.0, ECOSYSTEM:introduced=0,fixed=4.1.0; StarCitizenWiki EmbedVideo <= 4.0.0.

**Is there a fix for CVE-2026-57440?** Yes. starcitizenwiki/embedvideo (Packagist): upgrade to 4.1.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-57440 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-57440?** Check whether you run starcitizenwiki/embedvideo (Packagist) or StarCitizenWiki EmbedVideo at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- starcitizenwiki/embedvideo (Packagist): upgrade to 4.1.0 or later

  ```sh
  composer require starcitizenwiki/embedvideo:^4.1.0
  ```


## Technical details

The vulnerability is a stored cross-site scripting (XSS) flaw in the EmbedHtmlFormatter component. The vulnerable code directly incorporates URLs returned by getUrl() into iframe src attributes without sanitization. Multiple service-specific regex patterns (archiveorg, wistia, sharepoint) allow double-quote characters to be passed through, enabling escape of the src attribute and injection of HTML event handlers. The flaw requires $wgEmbedVideoRequireConsent to be set to false (non-default configuration). Any user with page-editing privileges can inject malicious parameters via embedvideo tags; the injected JavaScript executes automatically with autofocus attributes and affects all visitors viewing the compromised wiki page. The vulnerability is patched in version 4.1.0.

## Affected products

- StarCitizenWiki EmbedVideo <= 4.0.0

## Identifiers

- CVE-2026-57440
- GHSA-v65j-hff3-753c

## Timeline

- 2026-06-24: disclosed
- 2026-06-24: patched: Version 4.1.0 released
- 2026-09-25: advisory

## References

- [https://github.com/StarCitizenWiki/mediawiki-extensions-EmbedVideo/security/advisories/GHSA-v65j-hff3-753c](https://github.com/StarCitizenWiki/mediawiki-extensions-EmbedVideo/security/advisories/GHSA-v65j-hff3-753c)

## Related threats

- [StarCitizenWiki EmbedVideo stored XSS in EmbedHtmlFormatter](https://junglewise.ai/threats/cve-2026-55692-starcitizenwiki-embedvideo-stored-xss-in-embedhtmlformatter)
- [StarCitizenWiki EmbedVideo Stored XSS in EmbedHtmlFormatter](https://junglewise.ai/threats/cve-2026-55691-starcitizenwiki-embedvideo-stored-xss-in-embedhtmlformatter)
- [StarCitizenWiki EmbedVideo Stored XSS in exception text](https://junglewise.ai/threats/cve-2026-55690-starcitizenwiki-embedvideo-stored-xss-in-exception-text)
- [Star Citizen EmbedVideo Extension Stored XSS through wikitext caused by usage of non-reserved data attributes](https://junglewise.ai/threats/cve-2025-59839-star-citizen-embedvideo-extension-stored-xss-through-wikitext)