CVE-2026-43455 mctp: route: hold key->lock in mctp_flow_prepare_output()

In the Linux kernel, the following vulnerability has been resolved: mctp: route: hold key-lock in mctpflowprepareoutput mctpflowprepareoutput checks key-dev and may call mctpdevsetkey, but it does not hold key-lock while doing so. mctpdevsetkey and mctpdevreleasekey are annotated with...