An issue was discovered in the UnlinkedWikibase extension in MediaWiki before 1.39.6, 1.40.x before 1.40.2, and 1.41.x before 1.41.1. XSS can occur through an interface message. Error messages (in the $err var) are not escaped before being passed to Html::rawElement() in the getError() function in the Hooks class.
{
"versions": [
{
"introduced": "0"
},
{
"fixed": "1.39.6"
},
{
"introduced": "1.40.0"
},
{
"fixed": "1.40.2"
},
{
"introduced": "1.41.0"
},
{
"fixed": "1.41.1"
}
]
}