An issue was discovered in MediaWiki through 1.38.1. The lemma length of a Wikibase lexeme is currently capped at a thousand characters. Unfortunately, this length is not validated, allowing much larger lexemes to be created, which introduces various denial-of-service attack vectors within the Wikibase and WikibaseLexeme extensions. This is related to Special:NewLexeme and Special:NewProperty.
{ "cpes": [ "cpe:2.3:a:mediawiki:mediawiki:*:*:*:*:*:*:*:*" ], "severity": "High" }