CVE-2026-80783 in Linux
Summary
by MITRE • 09/04/2026
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.
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