Reverse proxy vulnerabilities

Requests from the reverse proxy to the identity-provider service for token discovery, introspection, and credential exchange do not verify the identity provider's server certificate. An attacker positioned on the network path between the proxy and the identity provider could impersonate the identity provider and issue forged authentication tokens accepted by the deployment.

In a particular authentication mode, the reverse proxy forwards requests for a bundled third-party administrative interface directly to it without first applying the gateway's own authentication requirement. All access control for this interface, which manages the credential store gating every other service, is delegated entirely to the third-party login mechanism.

A vulnerability in Reverse::Proxy versions before 0.04 for Perl: HTTP request smuggling via a percent-decoded PATH_INFO written unencoded to the upstream request line. PSGI hands PATH_INFO percent-decoded, so a %XX sequence becomes a raw byte. The proxy appends that byte string to the upstream base URL, and for an Upgrade tunnel writes it into a request line it serializes itself, re-encoding nothing. A path containing %0d%0a arrives at the upstream as a CRLF that ends the request line, and a decoded space, '?' or '#' truncates it the same way. Everything the client writes after the CRLF is read by the upstream as a second request.