Traefik 3.6.0 through 3.6.22 and 3.7.0 through 3.7.6 fail to enforce the crossProviderNamespaces allowlist for IngressRouteTCP service serversTransport references (the allowlist was only enforced for HTTP serversTransport references). A low-privileged Kubernetes user in a namespace not listed in crossProviderNamespaces can set serversTransport: foo@file on an IngressRouteTCP service, causing Traefik to accept the forbidden cross-provider reference and use a file-provider TCPServersTransport — including privileged backend mTLS client certificates, SPIFFE identity, or PROXY-protocol settings. This is fixed in 3.6.23 and 3.7.7.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
Present
Additional conditions required
Privileges Required
Low
Basic privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
None
No data leak
Integrity
None
No data modification
Availability
None
No disruption
CVSS Vector v4.0
Weakness Type (CWE)
References 3
https://github.com/traefik/traefik/commit/26c96a3935cafb473f4a5bae1886560d9aa4e…
disclosure@vulncheck.com
https://github.com/traefik/traefik/security/advisories/GHSA-42cj-m3vj-89wv
disclosure@vulncheck.com
https://www.vulncheck.com/advisories/traefik-before-ingressroutetcp-serverstran…
disclosure@vulncheck.com