UBUNTU-CVE-2021-33193

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    UBUNTU-CVE-2021-33193

    Published: 16 Aug 2021Last Modified: 22 Apr 2026
    Upstream:
    CVE-2021-33193
    Aliases:
    USN-5090-1

    Summary:

    Details: A crafted method sent through HTTP/2 will bypass validation and be forwarded by mod_proxy, which can lead to request splitting or cache poisoning. This issue affects Apache HTTP Server 2.4.17 to 2.4.48.

    References: https://ubuntu.com/security/CVE-2021-33193, https://portswigger.net/research/http2, https://ubuntu.com/security/notices/USN-5090-1, https://www.cve.org/CVERecord?id=CVE-2021-33193

    Affected packages

    Package

    Name: apache2

    Purl: pkg:deb/ubuntu/[email protected]?arch=source&distro=bionic

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -2.4.29-1ubuntu4.17

    Affected versions

    2.4.27-2ubuntu3
    2.4.29-1ubuntu1
    2.4.29-1ubuntu2
    2.4.29-1ubuntu3
    2.4.29-1ubuntu4
    2.4.29-1ubuntu4.1
    2.4.29-1ubuntu4.2
    2.4.29-1ubuntu4.3
    2.4.29-1ubuntu4.4
    2.4.29-1ubuntu4.5
    2.4.29-1ubuntu4.6
    2.4.29-1ubuntu4.7
    2.4.29-1ubuntu4.8
    2.4.29-1ubuntu4.10
    2.4.29-1ubuntu4.11
    2.4.29-1ubuntu4.12
    2.4.29-1ubuntu4.13
    2.4.29-1ubuntu4.14
    2.4.29-1ubuntu4.16

    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-2021-33193 | CVE-DB