KaTeX is a JavaScript library for TeX math rendering on the web. Code that uses KaTeX's "trust" option, specifically that provides a function to blacklist certain URL protocols, can be fooled by URLs in malicious inputs that use uppercase characters in the protocol. In particular, this can allow for malicious input to generate "javascript:" links in the output, even if the "trust" function tries to forbid this protocol via "trust: (context) => context.protocol !== 'javascript'". Upgrade to KaTeX v0.16.10 to remove this vulnerability.