CVE-2024-28244: KaTeX's maxExpand bypassed by Unicode sub/superscripts

KaTeX users who render untrusted mathematical expressions could encounter malicious input using \def or \newcommand that causes a near-infinite loop, despite setting maxExpand to avoid such loops. This can be used as an availability attack, where e.g. a client rendering another user’s KaTeX input will be unable to use the site due to memory overflow, tying up the main thread, or stack overflow.