CVE-2026-80781 in Linux
Tóm tắt
Bởi MITRE • 04/09/2026
In the Linux kernel, the following vulnerability has been resolved:
HID: core: fix OOB read of field->usage in hid_set_field()
hid_set_field() hands field->usage + offset to hid_dump_input() before the guard that bounds offset:
hid_dump_input(field->report->device, field->usage + offset, value);
if (offset >= field->report_count) {
hid_err(...); return -1; }
Under CONFIG_DEBUG_FS hid_dump_input() dereferences that pointer, with buf = hid_resolv_usage(usage->hid, NULL). The usage[] array is
allocated inline with the hid_field in hid_register_field() and holds field->maxusage entries, so an offset past it reads off the end of the kvzalloc()ed allocation and into a neighbouring object. Had the guard run first, offset < report_count <= maxusage would already have confined the pointer to the array.
A caller supplies such an offset today. picolcd_fb_send_tile() validates only report->maxfield before issuing hid_set_field(report->field[0], 11 + i, ...) for i = 0..31, so its
offsets are fixed at 11..42 and are never checked against the bound field. When the device registers that field with fewer usages, the framebuffer deferred-io work drives the read on every tile. KASAN reports a 4-byte slab-out-of-bounds read in hid_dump_input() below hid_set_field(), and the same boot logs "offset (1) exceeds report_count (1)" from the guard that runs only afterwards.
Move the hid_dump_input() call below the guard. Because field->maxusage >= field->report_count, the guard then establishes that field->usage + offset lies inside the array before it is dereferenced, for every caller and without changing behaviour on the valid path.
Discovered by XBOW, triaged by Baul Lee <[email protected]>
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