gRPC Authorization and Header Bypass

An authorization bypass vulnerability in gRPC-Go allows attackers to circumvent path-based access control by sending HTTP/2 requests with malformed :path pseudo-headers that omit the mandatory leading slash (e.g., 'Service/Method' instead of '/Service/Method'). This affects gRPC-Go servers using path-based authorization interceptors like google.golang.org/grpc/authz with deny rules for canonical paths but fallback allow rules. The vulnerability has a CVSS score of 9.1 (Critical) with network-based exploitation requiring no privileges or user interaction, enabling attackers to access restricted services and potentially exfiltrate or modify sensitive data.

The Rust libp2p Gossipsub implementation contains an integer overflow vulnerability that allows remote unauthenticated attackers to crash affected nodes by sending a single crafted PRUNE control message with an extremely large backoff value (e.g., u64::MAX). The vulnerability affects the libp2p-gossipsub Rust crate and enables trivial denial of service against any application exposing a Gossipsub listener. This vulnerability was discovered through responsible disclosure to the Ethereum Foundation bug bounty program by @revofusion, and while no active exploitation (KEV) status is indicated, the attack complexity is extremely low and a detailed proof-of-concept attack scenario has been publicly disclosed in the advisory.