** DISPUTED ** md2roff 1.7 has a stack-based buffer overflow via a Markdown file containing a large number of consecutive characters to be processed. NOTE: the vendor's position is that the product is not intended for untrusted input.
An issue was discovered in MediaWiki before 1.37.3 and 1.38.x before 1.38.1. The contributions-title, used on Special:Contributions, is used as page title without escaping. Hence, in a non-default configuration where a username contains HTML entities, it won't be escaped.