In the Linux kernel, the following vulnerability has been resolved:

firmware: arm_scmi: Unwind TX receiver mailbox setup failure

mailbox_chan_setup() can request an additional unidirectional TX
receiver channel after successfully acquiring the primary channel. If
that second request fails, the function returns immediately and leaves
the primary channel allocated.

Unwind the primary mailbox channel before returning the error so probe
deferral or other setup failures do not leave the channel busy for later
probe attempts.