CVE-2021-32779

CVE Details

Release Date:

2021-08-24

Description

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.

See more information about CVE-2021-32779 from MITRE CVE dictionary and NIST NVD

CVSS v3.0 metrics

NOTE: The following CVSS v3.0 metrics and score provided are preliminary and subject to review.

Base Score:	8.3	Base Metrics:	AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L
Access Vector:	Network	Attack Complexity:	Low
Privileges Required:	None	User Interaction:	None
Scope:	Changed	Confidentiality Impact:	Low
Integrity Impact:	Low	Availability Impact:	Low

Errata information

Platform	Errata	Release Date
Oracle Linux version 7 (istio)	ELSA-2021-9525	2021-11-10
Oracle Linux version 7 (istio)	ELSA-2021-9526	2021-11-09
Oracle Linux version 7 (kubernetes)	ELSA-2021-9526	2021-11-09
Oracle Linux version 7 (olcne)	ELSA-2021-9525	2021-11-10
Oracle Linux version 7 (olcne)	ELSA-2021-9526	2021-11-09
Oracle Linux version 8 (istio)	ELSA-2021-9525	2021-11-10
Oracle Linux version 8 (istio)	ELSA-2021-9546	2021-11-09
Oracle Linux version 8 (kubernetes)	ELSA-2021-9546	2021-11-09
Oracle Linux version 8 (olcne)	ELSA-2021-9525	2021-11-10
Oracle Linux version 8 (olcne)	ELSA-2021-9546	2021-11-09

This page is generated automatically and has not been checked for errors or omissions. For clarification or corrections please contact the Oracle Linux ULN team