CVE-2022-23632 Traefik skips the router TLS configuration when the host header is an FQDN

2022-02-1714:55:10

CWE-295

GitHub_M

www.cve.org

7.4 High

CVSS3

Attack Vector

NETWORK

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

NONE

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

8.3 High

AI Score

Confidence

High

0.001 Low

EPSS

Percentile

36.4%

JSON

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.

CNA Affected

[
  {
    "product": "traefik",
    "vendor": "traefik",
    "versions": [
      {
        "status": "affected",
        "version": "< 2.6.1"
      }
    ]
  }
]