CVE-2021-32777

    Dashboard / Vulnerabilities / CVE-2021-32777

    CVE-2021-32777

    Published: 24 Aug 2021Last Modified: 7 Aug 2026

    Summary:

    Details: Envoy is an open source L7 proxy and communication bus designed for large modern service oriented architectures. In affected versions when ext-authz extension is sending request headers to the external authorization service it must merge multiple value headers according to the HTTP spec. However, only the last header value is sent. This may allow specifically crafted requests to bypass authorization. Attackers may be able to escalate privileges when using ext-authz extension or back end service that uses multiple value headers for authorization. A specifically constructed request may be delivered by an untrusted downstream peer in the presence of ext-authz extension. Envoy versions 1.19.1, 1.18.4, 1.17.4, 1.16.5 contain fixes to the ext-authz extension to correctly merge multiple request header values, when sending request for authorization.

    References: https://github.com/envoyproxy/envoy/security/advisories/GHSA-6g4j-5vrw-2m8h, https://www.envoyproxy.io/docs/envoy/v1.19.0/version_history/version_history

    Affected packages

    Package

    Name:

    Purl:

    Affected ranges

    Type: GIT

    Events:

    Introduced- 8fb3cb86082b17144a80402f5367ae65f06083bd
    Fixed -72ec3eed50b4154cb6d2251667b4c1c1ddfaa266

    Affected versions

    1.19.0

    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-2021-32777 | CVE-DB