GHSA-55xv-f85c-248q

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    GHSA-55xv-f85c-248q

    Published: 17 Dec 2021Last Modified: 8 Jul 2026

    Summary: Regular Expression Denial of Service (ReDoS) in jsx-slack

    Details: jsx-slack v4.5.1 and earlier versions are vulnerable to a regular expression denial-of-service (ReDoS) attack. ### Impact 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. ```javascript /** @jsxImportSource jsx-slack */ import { Section } from 'jsx-slack' console.log( <Section> <blockquote> {[...Array(40)].map((_, i) => ( <p>{i + 1}</p> ))} </blockquote> </Section> ) ``` ### Patches _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) ### References - https://nvd.nist.gov/vuln/detail/CVE-2021-43838 - https://github.com/yhatt/jsx-slack/commit/36e4a10405e4c7745333e245fcc5029c02c7065d ### Credits Thanks to @hieki for finding out this vulnerability.

    Affected packages

    Package

    Name: jsx-slack

    Purl: pkg:npm/jsx-slack

    Affected ranges

    Type: SEMVER

    Events:

    Introduced- 0
    Fixed -4.5.1

    Affected versions

    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
    GHSA-55xv-f85c-248q | CVE-DB