We found the patch for CVE-2021-43838 in jsx-slack v4.5.1 is insufficient to save from Regular Expression Denial of Service (ReDoS) attack.
This vulnerability affects to jsx-slack v4.5.1 and earlier versions.
If attacker can put a lot of JSX elements into <blockquote>
tag with including multibyte characters, 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(() => (
<p>δΊ</p>
))}
</blockquote>
</section>
)
v4.5.1 has released by passing the test against ASCII characters but missed the case of multibyte characters.
https://github.com/yhatt/jsx-slack/security/advisories/GHSA-55xv-f85c-248q
jsx-slack v4.5.2 has updated regular expressions for escaping blockquote characters to prevent catastrophic backtracking. It is also including an updated test case to confirm rendering multiple tags in <blockquote>
with multibyte characters.
Thanks to @hieki for finding out this vulnerability.
github.com/yhatt/jsx-slack/commit/46bc88391d89d5fda4ce689e18ca080bcdd29ecc
github.com/yhatt/jsx-slack/releases/tag/v4.5.2
github.com/yhatt/jsx-slack/security
github.com/yhatt/jsx-slack/security/advisories/GHSA-55xv-f85c-248q
github.com/yhatt/jsx-slack/security/advisories/GHSA-hp68-xhvj-x6j6
nvd.nist.gov/vuln/detail/CVE-2021-43843