CVE-2021-36740

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    CVE-2021-36740

    Published: 14 Jul 2021Last Modified: 9 Jul 2026

    Summary:

    Details: Varnish Cache, with HTTP/2 enabled, allows request smuggling and VCL authorization bypass via a large Content-Length header for a POST request. This affects Varnish Enterprise 6.0.x before 6.0.8r3, and Varnish Cache 5.x and 6.x before 6.5.2, 6.6.x before 6.6.1, and 6.0 LTS before 6.0.8.

    References: https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/THV2DQA2GS65HUCKK4KSD2XLN3AAQ2V5/, https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZHBNLDEOTGYRIEQZBWV7F6VPYS4O2AAK/, https://docs.varnish-software.com/security/VSV00007/, https://varnish-cache.org/security/VSV00007.html, https://www.debian.org/security/2022/dsa-5088, https://github.com/varnishcache/varnish-cache/commit/82b0a629f60136e76112c6f2c6372cce77b683be, https://github.com/varnishcache/varnish-cache/commit/9be22198e258d0e7a5c41f4291792214a29405cf

    Affected packages

    Package

    Name:

    Purl:

    Affected ranges

    Type: GIT

    Events:

    Introduced- 99d036fe0b49c7487edb7dfd0da10fc2eef30505
    Fixed -None

    Affected versions

    varnish-6.0.7
    varnish-6.0.6
    varnish-6.0.5
    varnish-6.0.4
    varnish-6.0.3
    varnish-6.0.2
    varnish-6.0.1
    varnish-6.0.0

    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-2021-36740 | CVE-DB