Loading...
Skip to main content
GeekWala

CVE-2026-55691 — Vulnerability in starcitizenwiki/embedvideo — CVE...

HIGH

StarCitizenWiki Extension Embed Video: Stored XSS via unsanitized class passed to template

Published June 19, 2026Updated September 10, 2026Source: osv

Summary

### Summary The user supplied class value is fed directly into the sprintf call that creates HTML. You can add a quote to escape the class and then inject arbitrary html/javascript to the final output. ### Details The template [here](https://github.com/StarCitizenWiki/mediawiki-extensions-EmbedVideo/blob/a573a16d925ee0ea0d34b360856dc8ab0b88f822/includes/EmbedService/EmbedHtmlFormatter.php#L138) adds a figure with a class that is substituted in. This value is provided to sprintf [here](https://github.com/StarCitizenWiki/mediawiki-extensions-EmbedVideo/blob/a573a16d925ee0ea0d34b360856dc8ab0b88f822/includes/EmbedService/EmbedHtmlFormatter.php#L156), an unescaped version of the class supplied by the user. ``` $template = <<<HTML <figure class="%s" data-service="%s" %s %s> <div class="embedvideo-wrapper" %s>%s%s%s</div>%s </figure> HTML; ``` ### PoC Note the double quote immediately following the single quote to escape the class attribute in the template: ``` <youtube class='" onmouseover="alert(document.domain)' id="dQw4w9WgXcQ">dQw4w9WgXcQ</youtube> ``` ### Impact Arbitrary HTML can be inserted into the DOM by any user on any page, allowing for JavaScript to be executed.

Advisory Timeline

  • First published June 19, 2026 (115 days ago).
  • Last revised September 10, 2026 — 82 days after initial publication.

Remediation

Upgrade to the fixed version using your package manager.

Composer
Update starcitizenwiki/embedvideo to 4.1.0 or later
composer require "starcitizenwiki/embedvideo:^4.1.0"

After upgrading, run your dependency scanner again to confirm the vulnerability is resolved.

Affected Packages (1)

Affects 1 ecosystem: packagist (1).

PackageEcosystemAffectedFixed In
starcitizenwiki/embedvideo
packagist
3.0.0, 3.0.1, 3.0.2, 3.0.3 (+22 more)4.1.0

Vulnerability Classification

Common Weakness Enumeration (CWE) identifiers for this vulnerability type.

CVSS Score Breakdown

What the CVSS (Common Vulnerability Scoring System) 8.6 score means for each attack dimension.

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
Low
Availability
Low

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L

References

Frequently Asked Questions

What is CVE-2026-55691?
StarCitizenWiki Extension Embed Video: Stored XSS via unsanitized class passed to template This vulnerability has been assigned a severity rating of HIGH (CVSS score: 8.6/10).
How do I check if my project is affected by CVE-2026-55691?
CVE-2026-55691 affects starcitizenwiki/embedvideo. Use GeekWala's free vulnerability scanner to check your dependencies against CVE-2026-55691 and 200,000+ other known vulnerabilities.

Severity & Exploitability

CVSS Score
8.6

High exploitability or significant impact. Prioritize remediation within days.

Also Known As

GHSA-7h5p-637f-jfr7

Related CVEs

  • CVE-2025-59839
    HIGH

    Star Citizen EmbedVideo Extension Stored XSS through wikitext caused by usage of non-reserved data attributes

  • CVE-2026-65954
    HIGH

    PHPCSUtils: Remote code execution via eval() in AbstractArrayDeclarationSniff::getActualArrayKey()

  • CVE-2026-61825
    HIGH

    code16/sharp has a stored XSS via data-html-content Sanitizer Bypass

More Packagist advisories

Check if you're affected

Scan your dependencies to see if this vulnerability affects your projects.

Scan Your Dependencies