mnl has segmentation fault and invalid memory read in `mnl::cb_run`

The function mnl::cb_run is marked as safe but exhibits unsound behavior when processing malformed Netlink message buffers.

Passing a crafted byte slice to mnl::cb_run can trigger memory violations. The function does not sufficiently validate the input buffer structure before processing, leading to out-of-bounds reads.

This vulnerability allows an attacker to cause a Denial of Service (segmentation fault) or potentially read unmapped memory by providing a malformed Netlink message.