CVE-2021-32779

Envoy is an open source L7 proxy and communication bus designed for large modern service oriented architectures. In affected versions envoy incorrectly handled a URI '#fragment' element as part of the path element. Envoy is configured with an RBAC filter for authorization or similar mechanism with an explicit case of a final "/admin" path element, or is using a negative assertion with final path element of "/admin". The client sends request to "/app1/admin#foo". In Envoy prior to 1.18.0, or 1.18.0+ configured with path_normalization=false. Envoy treats fragment as a suffix of the query string when present, or as a suffix of the path when query string is absent, so it evaluates the final path element as "/admin#foo" and mismatches with the configured "/admin" path element. In Envoy 1.18.0+ configured with path_normalization=true. Envoy transforms this to /app1/admin%23foo and mismatches with the configured /admin prefix. The resulting URI is sent to the next server-agent with the offending "#foo" fragment which violates RFC3986 or with the nonsensical "%23foo" text appended. A specifically constructed request with URI containing '#fragment' element delivered by an untrusted client in the presence of path based request authorization resulting in escalation of Privileges when path based request authorization extensions. Envoy versions 1.19.1, 1.18.4, 1.17.4, 1.16.5 contain fixes that removes fragment from URI path in incoming requests.
Configurations

Configuration 1 (hide)

OR cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*
cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*
cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*
cpe:2.3:a:envoyproxy:envoy:1.19.0:*:*:*:*:*:*:*

History

25 Oct 2022, 15:56

Type Values Removed Values Added
CWE CWE-863 CWE-697

15 Jun 2022, 15:49

Type Values Removed Values Added
CPE cpe:2.3:a:envoyproxy:envoy:1.19.0:*:*:*:*:*:*:*

07 Sep 2021, 18:51

Type Values Removed Values Added
CVSS v2 : 7.5
v3 : 9.8
v2 : 7.5
v3 : 8.3

01 Sep 2021, 00:33

Type Values Removed Values Added
CVSS v2 : unknown
v3 : 8.6
v2 : 7.5
v3 : 9.8
CPE cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*
CWE CWE-551
References (MISC) https://www.envoyproxy.io/docs/envoy/v1.19.0/version_history/version_history - (MISC) https://www.envoyproxy.io/docs/envoy/v1.19.0/version_history/version_history - Vendor Advisory
References (CONFIRM) https://github.com/envoyproxy/envoy/security/advisories/GHSA-r222-74fw-jqr9 - (CONFIRM) https://github.com/envoyproxy/envoy/security/advisories/GHSA-r222-74fw-jqr9 - Third Party Advisory

24 Aug 2021, 21:15

Type Values Removed Values Added
New CVE

Information

Published : 2021-08-24 21:15

Updated : 2024-02-04 21:47


NVD link : CVE-2021-32779

Mitre link : CVE-2021-32779

CVE.ORG link : CVE-2021-32779


JSON object : View

Products Affected

envoyproxy

  • envoy
CWE
CWE-697

Incorrect Comparison

CWE-551

Incorrect Behavior Order: Authorization Before Parsing and Canonicalization

CWE-863

Incorrect Authorization