{
"id": "GHSA-7h5p-637f-jfr7",
"aliases": [
"CVE-2026-55691"
],
"details": "### Summary\nThe 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.\n\n### Details\nThe 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.\n\n```\n$template = <<<HTML\n <figure class=\"%s\" data-service=\"%s\" %s %s>\n <div class=\"embedvideo-wrapper\" %s>%s%s%s</div>%s\n </figure>\nHTML;\n```\n\n### PoC\nNote the double quote immediately following the single quote to escape the class attribute in the template:\n```\n<youtube class='\" onmouseover=\"alert(document.domain)' id=\"dQw4w9WgXcQ\">dQw4w9WgXcQ</youtube>\n```\n\n### Impact\nArbitrary HTML can be inserted into the DOM by any user on any page, allowing for JavaScript to be executed.",
"summary": "StarCitizenWiki Extension Embed Video: Stored XSS via unsanitized class passed to template",
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "4.1.0"
}
]
}
],
"package": {
"name": "starcitizenwiki/embedvideo",
"ecosystem": "Packagist"
},
"database_specific": {
"last_known_affected_version_range": "<= 4.0.0"
}
}
],
"modified": "2026-06-19T21:15:03Z",
"severity": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L"
}
],
"published": "2026-06-19T21:15:03Z",
"references": [
{
"url": "https://github.com/StarCitizenWiki/mediawiki-extensions-EmbedVideo/security/advisories/GHSA-7h5p-637f-jfr7",
"type": "WEB"
},
{
"url": "https://github.com/StarCitizenWiki/mediawiki-extensions-EmbedVideo/commit/370156335b325bb81d14d89edf0a1f2643d50a84",
"type": "WEB"
},
{
"url": "https://github.com/StarCitizenWiki/mediawiki-extensions-EmbedVideo",
"type": "PACKAGE"
},
{
"url": "https://github.com/StarCitizenWiki/mediawiki-extensions-EmbedVideo/releases/tag/v4.1.0",
"type": "WEB"
}
],
"schema_version": "1.4.0",
"database_specific": {
"cwe_ids": [
"CWE-79",
"CWE-80"
],
"severity": "HIGH",
"github_reviewed": true,
"nvd_published_at": null,
"github_reviewed_at": "2026-06-19T21:15:03Z"
}
}