CVE-2026-55691
A quote in the class value can terminate the class attribute and inject arbitrary HTML attributes or markup into the rendered page.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.48%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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, 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.
- CVSS 3.1
- 8.6 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L
- EPSS
- 0.48% probability · 41th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-79
- Source
- security-advisories@github.com
EPSS 0.5% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://github.com/StarCitizenWiki/mediawiki-extensions-EmbedVideo/commit/370156335b325bb81d14d89edf0a1f2643d50a84
- https://github.com/StarCitizenWiki/mediawiki-extensions-EmbedVideo/releases/tag/v4.1.0
- https://github.com/StarCitizenWiki/mediawiki-extensions-EmbedVideo/security/advisories/GHSA-7h5p-637f-jfr7
- https://github.com/StarCitizenWiki/mediawiki-extensions-EmbedVideo/security/advisories/GHSA-7h5p-637f-jfr7
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.