PraisonAI is a multi-agent teams system. Prior to 0.1.6, praisonai_platform/services/auth_service.py falls back to the public dev-secret-change-me HS256 signing key when PLATFORM_JWT_SECRET is unset, while the startup and token-issuance guards are disabled because PLATFORM_ENV also defaults to dev. An unauthenticated attacker can sign a JWT containing an attacker-chosen sub value, and AuthService._verify_token() accepts it as an authenticated identity, enabling user or workspace-owner impersonation when a target identifier is known. This vulnerability is fixed in praisonai-platform 0.1.6.