CVE-2026-17053 SMBus callback-removal syscalls accept an unvalidated user pointer, letting user threads manipulate kernel callback state

The SMBus driver API exposed smbussmbalertremovecb and smbushostnotifyremovecb as Zephyr syscalls. Their verifiers in drivers/smbus/smbushandlers.c validated only the dev argument with KSYSCALLOBJdev, KOBJDRIVERSMBUS and forwarded the caller-supplied struct smbuscallback cb pointer into kernel-mo...