In MediaWiki through 1.37, the Special:ImportFile URI (aka FileImporter) allows XSS, as demonstrated by the clientUrl parameter.
{ "binaries": [ { "binary_name": "mediawiki", "binary_version": "1:1.27.4-3" }, { "binary_name": "mediawiki-classes", "binary_version": "1:1.27.4-3" } ] }
{ "binaries": [ { "binary_name": "mediawiki", "binary_version": "1:1.31.7-1" }, { "binary_name": "mediawiki-classes", "binary_version": "1:1.31.7-1" } ] }
{ "binaries": [ { "binary_name": "mediawiki", "binary_version": "1:1.35.6-1" }, { "binary_name": "mediawiki-classes", "binary_version": "1:1.35.6-1" } ] }
{ "binaries": [ { "binary_name": "mediawiki", "binary_version": "1:1.39.7-1" }, { "binary_name": "mediawiki-classes", "binary_version": "1:1.39.7-1" } ] }
{ "binaries": [ { "binary_name": "mediawiki", "binary_version": "1:1.43.1+dfsg-1" }, { "binary_name": "mediawiki-classes", "binary_version": "1:1.43.1+dfsg-1" } ] }