An issue was discovered in the CheckUser extension for MediaWiki through 1.39.3. In Special:CheckUser, a check of the "get edits" type is vulnerable to HTML injection through the User-Agent HTTP request header.
{
"cpes": [
"cpe:2.3:a:mediawiki:mediawiki:*:*:*:*:*:*:*:*"
],
"severity": "Medium"
}