CVE-2021-32777 Information

Description

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.

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L

Reference

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

Attack Complexity

LOW

Privileges Required

NONE

User Interaction Required

NONE

Scope

NONE

Confidentiality Impact

CHANGED

Integrity Impact

LOW

Availability Impact

LOW

Base Score

LOW

Base Severity

8.3