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CVE-2021-43843

5.3 · MEDIUM

jsx-slack is a package for building JSON objects for Slack block kit surfaces from JSX.

Published Dec 20, 2021CWE-400EPSS 1.98%

Overview

CVE-2021-43843 is a medium-severity vulnerability. It was published on December 20, 2021 and has a CVSS 3.1 base score of 5.3 (MEDIUM).

This vulnerability has a CVSS 3.1 base score of 5.3, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

Technical 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.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

GitHubgithub.com/yhatt/jsx-slack/commit/46bc88391d89d5fda4ce689e18ca080bcdd29eccGitHubgithub.com/yhatt/jsx-slack/releases/tag/v4.5.2GitHubgithub.com/yhatt/jsx-slack/security/advisories/GHSA-55xv-f85c-248qGitHubgithub.com/yhatt/jsx-slack/security/advisories/GHSA-hp68-xhvj-x6j6GitHubgithub.com/yhatt/jsx-slack/commit/46bc88391d89d5fda4ce689e18ca080bcdd29eccGitHubgithub.com/yhatt/jsx-slack/releases/tag/v4.5.2GitHubgithub.com/yhatt/jsx-slack/security/advisories/GHSA-55xv-f85c-248qGitHubgithub.com/yhatt/jsx-slack/security/advisories/GHSA-hp68-xhvj-x6j6

How CyberStrike helps

Frequently asked questions

What is CVE-2021-43843?

CVE-2021-43843 is a medium-severity vulnerability. It was published on December 20, 2021 and has a CVSS 3.1 base score of 5.3 (MEDIUM).

How severe is CVE-2021-43843?

This vulnerability has a CVSS 3.1 base score of 5.3, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2021-43843?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2021-43843?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-43843 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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