CVE-2026-19185 Unvalidated user-supplied buffer pointers in the I3C do_ccc system call handler allow kernel memory read/write from user mode

The system-call verifier for i3cdoccc in drivers/i3c/i3chandlers.c validated the outer struct i3ccccpayload, the broadcast ccc.data buffer and the targets.payloads array, but did not validate the per-target data buffers those array elements point at. Each struct i3cccctargetpayload carries its ow...