Anytype Heart's gRPC API client challenge verification can be bypassed on localhost

Impact

The challenge-based authentication for the local gRPC client API can be bypassed, allowing an attacker to gain access without the 4-digit code.

Affected components:

• Anytype Desktop (all platforms) ≤ v0.48.2
• Anytype-CLI (headless deployments) ≤ v0.1.9

Not affected:

• Anytype mobile apps (iOS, Android) - do not expose a local gRPC server

Who is impacted:
This vulnerability is scoped to localhost. The gRPC and gRPC-Web ports bind to 127.0.0.1 only and are not exposed to the local network or internet.

Exploitation requires:

• Local user-level access to the machine running Anytype
• Discovery of the randomized listening port
• A running Anytype instance

Anytype-CLI headless deployments may be at higher risk only if an administrator has chosen to set up their own reverse proxy and configured it in a way that
exposes gRPC or gRPC-Web ports to an external network. By default, these ports are not externally accessible and there is no built-in mechanism to expose them.

Patches

• anytype-heart library: v0.48.4
• Anytype Desktop: v0.54.5
• Anytype-CLI: v0.1.11

Workarounds

• Desktop users: No immediate action required. The vulnerability requires existing local access to the machine.
• Anytype-CLI administrators: If using a custom reverse proxy, ensure it does not expose gRPC or gRPC-Web ports to external networks.