Bug 2055877 (CVE-2022-23632)

Summary:	CVE-2022-23632 traefik: TLS configuration falls back to the default configuration that might not correspond to the configured one
Product:	[Other] Security Response	Reporter:	Pedro Sampaio <psampaio>
Component:	vulnerability	Assignee:	Nobody <nobody>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	Keywords:	Security
Target Milestone:	---
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	2055878

Description Pedro Sampaio 2022-02-17 20:35:30 UTC

Traefik is an HTTP reverse proxy and load balancer. Prior to version 2.6.1, Traefik skips the router transport layer security (TLS) configuration when the host header is a fully qualified domain name (FQDN). For a request, the TLS configuration choice can be different than the router choice, which implies the use of a wrong TLS configuration. When sending a request using FQDN handled by a router configured with a dedicated TLS configuration, the TLS configuration falls back to the default configuration that might not correspond to the configured one. If the CNAME flattening is enabled, the selected TLS configuration is the SNI one and the routing uses the CNAME value, so this can skip the expected TLS configuration. Version 2.6.1 contains a patch for this issue. As a workaround, one may add the FDQN to the host rule. However, there is no workaround if the CNAME flattening is enabled.

https://github.com/traefik/traefik/security/advisories/GHSA-hrhx-6h34-j5hc
https://github.com/traefik/traefik/pull/8764
https://github.com/traefik/traefik/releases/tag/v2.6.1