jsx-slack v4.5.1 and earlier versions are vulnerable to a regular expression denial-of-service (ReDoS) attack.
If attacker can put a lot of JSX elements into <blockquote>
tag, an internal regular expression for escaping characters may consume an excessive amount of computing resources.
/** @jsxImportSource jsx-slack */
import { Section } from 'jsx-slack'
console.log(
<section>
<blockquote>
{[...Array(40)].map((_, i) => (
<p>{i + 1}</p>
))}
</blockquote>
</section>
)
_See also: https://github.com/yhatt/jsx-slack/security/advisories/GHSA-hp68-xhvj-x6j6_
jsx-slack v4.5.2 has updated regular expressions to prevent catastrophic backtracking.
jsx-slack v4.5.1 also had patched a workaround. It has no problems to contents with ASCII characters, but still vulnerable to contents with multibyte characters. (https://github.com/yhatt/jsx-slack/commit/36e4a10405e4c7745333e245fcc5029c02c7065d)
Thanks to @hieki for finding out this vulnerability.