CVE-2026-98499

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

HID: wacom: fix OOB read in wacom wac pen serial enforce()

The 'wacom wac pen serial enforce()' function may calculate and pass an invalid offset to hid field extract(), resulting in memory reads at incorrect addresses -- possibly beyond the end of the report. If a field in the HID descriptor lists more usages than its Report Count actually reserves space for, the function's inner 'j' will walk past the end of the field:

for (i = 0; i < report->maxfield; i++) {
	for (j = 0; j < report->field[i]->maxusage; j++) {
		...
		value = hid field extract(hdev, raw data + 1,
					 offset + j * size, size);

A descriptor listing 12288 usages against Report Count 1 has the loop extract the usage at index 12287 from bit offset 98296 -- about 12 KB past a 2-byte received report. The value is stored in wacom wac->serial[0] and can reach userspace as an MSC SERIAL event, making this an information disclosure.

Clamp the loop to field->report count, the number of value slots the report holds. Value slots past the last declared usage are still scanned; they reuse that usage (HID 1.11, 6.2.2.8).

Verified on v6.12.105 with a UHID reproducer: a 2-byte report from such a descriptor trips KASAN before the patch and not after it.