UBUNTU-CVE-2021-42717

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    UBUNTU-CVE-2021-42717

    Published: 7 Dec 2021Last Modified: 20 May 2026
    Upstream:
    CVE-2021-42717
    Aliases:
    USN-6370-1

    Summary:

    Details: ModSecurity 3.x through 3.0.5 mishandles excessively nested JSON objects. Crafted JSON objects with nesting tens-of-thousands deep could result in the web server being unable to service legitimate requests. Even a moderately large (e.g., 300KB) HTTP request can occupy one of the limited NGINX worker processes for minutes and consume almost all of the available CPU on the machine. Modsecurity 2 is similarly vulnerable: the affected versions include 2.8.0 through 2.9.4.

    References: https://ubuntu.com/security/CVE-2021-42717, https://github.com/SpiderLabs/ModSecurity/issues/2647, https://ubuntu.com/security/notices/USN-6370-1, https://www.cve.org/CVERecord?id=CVE-2021-42717

    Affected packages

    Package

    Name: modsecurity-apache

    Purl: pkg:deb/ubuntu/modsecurity-apache?arch=source&distro=esm-apps%2Fxenial

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -2.9.0-1ubuntu0.1~esm1

    Affected versions

    2.9.0-1

    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
    UBUNTU-CVE-2021-42717 | CVE-DB