KaTeX \htmlData does not validate attribute names
### Impact
KaTeX users who render untrusted mathematical expressions with `renderToString` could encounter malicious input using `\htmlData` that runs arbitrary JavaScript, or generate invalid HTML.
### Patches
Upgrade to KaTeX v0.16.21 to remove this vulnerability.
### Workarounds
- Avoid use of or turn off the `trust` option, or set it to forbid `\htmlData` commands.
- Forbid inputs containing the substring `"\\htmlData"`.
- Sanitize HTML output from KaTeX.
### Details
`\htmlData` did not validate its attribute name argument, allowing it to generate invalid or malicious HTML that runs scripts.
### For more information
If you have any questions or comments about this advisory:
- Open an issue or security advisory in the KaTeX repository
https://github.com/KaTeX/KaTeX/
- Email us at [katex-security@mit.edu](mailto:katex-security@mit.edu)