Vulnerability Monitor

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CVE-2021-32777

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.

Published

2021-08-24T21:15:06.970

Last Modified

2024-11-21T06:07:43.210

Status

Modified

Source

[email protected]

Severity

CVSSv3.1: 8.6 (HIGH)

CVSSv2 Vector

AV:N/AC:L/Au:N/C:P/I:P/A:P

  • Access Vector: NETWORK
  • Access Complexity: LOW
  • Authentication: NONE
  • Confidentiality Impact: PARTIAL
  • Integrity Impact: PARTIAL
  • Availability Impact: PARTIAL
Exploitability Score

10.0

Impact Score

6.4

Weaknesses
  • Type: Secondary
    CWE-551
    CWE-863
  • Type: Primary
    CWE-863
Affected Vendors & Products
Type Vendor Product Version/Range Vulnerable?
Application envoyproxy envoy < 1.16.5 Yes
Application envoyproxy envoy < 1.17.4 Yes
Application envoyproxy envoy < 1.18.4 Yes
Application envoyproxy envoy 1.19.0 Yes
References