CVE-2026-80783

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

HID: magicmouse: prevent unbounded recursion in magicmouse raw event()

magicmouse raw event() handles DOUBLE REPORT ID (0xf7) packets, which pack two touch reports into one, by splitting the packet and calling itself on each half. The only guard against runaway recursion is a "size < 1" check, which stops zero-sized calls but does not bound the recursion depth.

A malicious HID device that matches this driver can send a report starting with DOUBLE REPORT ID and filled with the sequence [0xf7, 0x00]. Each level consumes two bytes and recurses on the remainder, so an incoming report of up to HID MAX BUFFER SIZE (16 KiB) drives roughly 8000 nested calls. That easily exhausts the 16 KiB kernel stack, leading to a stack overflow: a panic with CONFIG VMAP STACK, or memory corruption without it.

A double report only ever wraps two normal reports; it is never legitimately nested. Refuse to re-enter the DOUBLE REPORT ID case from a recursive call so the recursion depth is bounded to two, while all valid packets keep being parsed exactly as before.