CVE-2021-43843

Public Exploit
Insufficient patch for Regular Expression Denial of Service (ReDoS) to jsx-slack v4.5.1

Description

jsx-slack is a package for building JSON objects for Slack block kit surfaces from JSX. The maintainers found the patch for CVE-2021-43838 in jsx-slack v4.5.1 is insufficient tfor protection from a Regular Expression Denial of Service (ReDoS) attack. If an 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. v4.5.1 passes the test against ASCII characters but misses the case of multibyte characters. 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.

Category

5.3
CVSS
Severity: Medium
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.53%
Third-Party Advisory github.com Third-Party Advisory github.com Third-Party Advisory github.com Third-Party Advisory github.com
Affected: yhatt jsx-slack
Published at:
Updated at:

References

Link Tags
https://github.com/yhatt/jsx-slack/security/advisories/GHSA-hp68-xhvj-x6j6 patch third party advisory exploit
https://github.com/yhatt/jsx-slack/security/advisories/GHSA-55xv-f85c-248q patch third party advisory exploit
https://github.com/yhatt/jsx-slack/commit/46bc88391d89d5fda4ce689e18ca080bcdd29ecc third party advisory patch
https://github.com/yhatt/jsx-slack/releases/tag/v4.5.2 third party advisory release notes

Frequently Asked Questions

What is the severity of CVE-2021-43843?
CVE-2021-43843 has been scored as a medium severity vulnerability.
How to fix CVE-2021-43843?
To fix CVE-2021-43843, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-43843 being actively exploited in the wild?
It is possible that CVE-2021-43843 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~1% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-43843?
CVE-2021-43843 affects yhatt jsx-slack.
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