CVE-2021-43843

    Dashboard / Vulnerabilities / CVE-2021-43843

    CVE-2021-43843

    Published: 20 Dec 2021Last Modified: 9 Jul 2026

    Summary:

    Details: 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.

    References: https://github.com/yhatt/jsx-slack/releases/tag/v4.5.2, https://github.com/yhatt/jsx-slack/commit/46bc88391d89d5fda4ce689e18ca080bcdd29ecc, https://github.com/yhatt/jsx-slack/security/advisories/GHSA-55xv-f85c-248q, https://github.com/yhatt/jsx-slack/security/advisories/GHSA-hp68-xhvj-x6j6

    Affected packages

    Package

    Name:

    Purl:

    Affected ranges

    Type: GIT

    Events:

    Introduced- 0
    Fixed -2fc5567b48bf8cbb8e9902c09e2b5a56f4068e19

    Affected versions

    v4.5.1
    v4.5.0

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High
    CVE-2021-43843 | CVE-DB