Wheels 3.0.0 through 4.1.1 can disclose detailed exceptions when allowIPBasedDebugAccess=true (disabled by default). An allowed administrator request changes error/debug-display settings in shared application scope. If it overlaps with an unauthorized client's request that raises an error, that client can receive full exception details, including tag context or a serialized exception, and any sensitive data they contain. This race does not bypass the production gate protecting developer tools. This is fixed in 4.1.2.