In MediaWiki through 1.37, XSS can occur in Wikibase because an external identifier property can have a URL format that includes a $1 formatter substitution marker, and the javascript: URL scheme (among others) can be used.
https://phabricator.wikimedia.org/T297570
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/Z7JNQA53K675TQBBJPZRAG5ZT6XES3IS/
https://gerrit.wikimedia.org/r/q/I37ece1dfdc80d38055067c9c4fa73ba591acd8bd
Source: Mitre, NVD
Published: 2021-12-24
Updated: 2024-11-21
Base Score: 4.3
Vector: CVSS2#AV:N/AC:M/Au:N/C:N/I:P/A:N
Severity: Medium
Base Score: 6.1
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
EPSS: 0.00243