CVE-2026-89999

Description

In the Linux kernel, the following vulnerability has been resolved: HID: wacom: validate report length in wacom_intuos_pro2_bt_irq wacom_intuos_pro2_bt_irq() receives the wire report length in `len` but never consults it before parsing. After the report-id gate it unconditionally calls wacom_intuos_pro2_bt_pen() and then, selected by features.type, a fixed chain of sub-parsers, none of which receive `len`: wacom_intuos_pro2_bt_pen(wacom); if (type == INTUOSP2_BT || type == INTUOSP2S_BT) { wacom_intuos_pro2_bt_touch(wacom); wacom_intuos_pro2_bt_pad(wacom); wacom_intuos_pro2_bt_battery(wacom); } else { wacom_intuos_gen3_bt_pad(wacom); wacom_intuos_gen3_bt_battery(wacom); } Each sub-parser dereferences wacom->data at fixed offsets. The furthest byte touched on each branch is: INTUOSP2_BT / INTUOSP2S_BT: wacom_intuos_pro2_bt_pad() reads data[285] (the touchring byte), so the report must be at least 286 bytes; INTUOSHT3_BT ("gen3"): wacom_intuos_gen3_bt_battery() reads data[45], so the report must be at least 46 bytes. features.type is selected from the VID/PID id_table entry and wacom_setup_device_quirks() force-registers the pen/pad/touch inputs for that type independent of the report descriptor, so a malicious or malfunctioning paired/spoofed Bluetooth peripheral can advertise that VID/PID and send an undersized report that still satisfies the data[0] == 0x80/0x81 gate. The driver then reads past the received report and forwards the bytes to userspace via evdev (MSC_SERIAL / ABS_MISC / ABS_WHEEL on the pen and pad input nodes), an out-of-bounds read with a concrete userspace read-back channel, and a true out-of-bounds read on transports whose backing buffer is sized to the (small) report descriptor rather than a fixed-size staging buffer. This is the same class of bug commit 2f1763f62909 ("HID: wacom: fix out-of-bounds read in wacom_intuos_bt_irq") already hardened in the sibling wacom_intuos_bt_irq(), which guards each report id against its minimum length before parsing. Guard wacom_intuos_pro2_bt_irq() the same way: before parsing, reject reports shorter than the furthest offset the selected branch actually dereferences, warn, and bail out. Because the whole pen/touch/pad/ battery chain runs unconditionally per branch, a single up-front check against the maximum offset (286 bytes for INTUOSP2_BT/INTUOSP2S_BT, 46 bytes for the gen3 branch) bounds every sub-parser. Returning 0 on a short report also skips those calls for the same malformed report, which is the safe, conservative behavior.

Predictions

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

References

• https://git.kernel.org/stable/c/0cdc6cb242dd8d2731956fdf3390de094482a4b2
• https://git.kernel.org/stable/c/114af803e409a68e52516810ecd24df4d8ce0c68
• https://git.kernel.org/stable/c/1bfc0547b81d5861443420d19b5ed2fd533cd17f
• https://git.kernel.org/stable/c/74ec08f7b81c2726578039ca6dea0fec136c38ea
• https://git.kernel.org/stable/c/84781a1f3c5dc6650480be9329e6e8528939eaa0
• https://git.kernel.org/stable/c/96dd0af7597aba2d80cc97e2f66e8b72d30ba125
• https://git.kernel.org/stable/c/a8e04f3f894ccb52cfcd7e60125a9f35da4a616d
• https://git.kernel.org/stable/c/d2844f3fcd058113acbe0aa110ab13ef28b98d9f