frp vulnerabilities

frp 0.41.0 through 0.71.1 contains a missing authentication vulnerability that allows unauthenticated remote attackers to access pprof debug endpoints because handlers are registered on the root mux outside Basic Authentication. Attackers can query /debug/pprof/ endpoints on frps dashboard or frpc admin listeners to obtain cmdline, goroutine stacks, heap profiles, and trigger CPU profiling.

frp versions 0.53.0 through 0.70.1 have a vulnerability in the optional SSH Tunnel Gateway in pkg/ssh/server.go, where parsing an SSH exec channel request adds 4 to an attacker-controlled length. A length of 0xFFFFFFFF makes the uint32 addition wrap to 3, defeating the bounds check and causing a panic in TunnelServer.handleNewChannel. When no authorized-keys file is configured, an unauthenticated peer can reach this phase before the frp token is checked, and a single five-byte request terminates the frps process and drops every active tunnel. The issue is fixed in version 0.70.1.

From 0.43.0 to 0.68.0, frp contains an authentication bypass in the HTTP vhost routing path when routeByHTTPUser is used as part of access control. In proxy-style requests, routing uses the username from Proxy-Authorization to select the routeByHTTPUser backend, while the access control check uses credentials from the regular Authorization header, allowing an attacker to access a backend protected by httpUser/httpPassword even with an incorrect Proxy-Authorization password. This is fixed in 0.68.1.