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CVE-2026-63916
HID: wacom: Fix OOB write in wacom_hid_set_device_mode()
Published 2026-07-19 (3 months ago) by the Linux kernel CNA. Subsystem drivers/hid. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-63916 in every release this site tracks, and what each one means in practice. Every status below is the one the Debian Security Team publishes for this CVE. source
| Release | Status | Version | What this means |
|---|---|---|---|
| Debian 12bookworm | fixed | 6.1.176-1 | Update the kernel and reboot. Fixed in 6.1.176-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixed | 6.12.94-1 | Update the kernel and reboot. Fixed in 6.12.94-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.0.12-1 | Update the kernel and reboot. Fixed in 7.0.12-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.0.12-1 | Update the kernel and reboot. Fixed in 7.0.12-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
wacom_hid_set_device_mode() currently assumes that the HID_DG_INPUTMODE usage is always located in the first field (field[0]) of the feature report. However, a device can specify HID_DG_INPUTMODE in a different field. If HID_DG_INPUTMODE is in a field other than the first one and the first field has a report_count smaller than the usage_index of HID_DG_INPUTMODE, this leads to an out-of-bounds write to r->field[0]->value. Fix this by storing the field index of HID_DG_INPUTMODE in 'struct hid_data' during feature mapping. In wacom_hid_set_device_mode(), use this stored field index to access the correct field and add bounds checks to ensure both the field index and the value index are within valid ranges before writing.
Where it lives
The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.
drivers/hid/wacom_sys.c
drivers/hid/wacom_wac.h
- What this is
- HID WACOM DRIVERMAINTAINERS section matched on drivers/hid/wacom_* · linux-input@vger.kernel.org · Maintained
- Kernel module
- wacom
Check it on the machine
grep -wE 'CONFIG_HID|CONFIG_HID_SUPPORT|CONFIG_HID_WACOM' /boot/config-$(uname -r)Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.
lsmod | grep -w wacomPrints a line if that module is loaded right now, and nothing if it is not. One that is not loaded can still be loaded later by anything that needs it.
Show whether Debian builds this, per release
Debian builds this, but not on every flavour. At least one release below builds the code on some of its kernel flavours and not on others, so the answer depends on the architecture and flavour installed.
- bookworm, trixie, forky, sidMnot built on amd64/cloud-amd64, arm64/cloud-arm64
- M
- a module where it is built at all; some flavours do not build it
- Build switches
- CONFIG_HID, CONFIG_HID_SUPPORT, CONFIG_HID_WACOM
- Reads as
- all on means the file is compiled; any one off means it is not.
From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages
Signals
- Published
- 2026-07-19 (3 months ago)source
- CVSS
- 8.8 high
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- adjacent network (AV:A)source
- EPSS
- 0.35%, higher than 27.6% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- drivers/hid
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 3.18 | 5.10.259 | 2add311d9964 |
| 3.18 | 5.15.210 | 83bd8a5756a3 |
| 3.18 | 6.1.176 | 5716a293fb19 |
| 3.18 | 6.6.143 | ed598de9f615 |
| 3.18 | 6.12.93 | 43e7c02d6090 |
| 3.18 | 6.18.35 | b8338111e141 |
| 3.18 | 7.0.12 | 5db3fca0cec7 |
| 3.18 | 7.1 | c0a8899e02dd |
Why the CNA scored it this way
Quoted from the kernel CNA's own scoring file, word for word. A highlighted metric carries the most severe value CVSS v3.1 defines for it, which is what pushes the score up. source
- AV:AAttack vector, adjacent network
- The bug is triggered when the kernel probes a Wacom HID device whose report descriptor is supplied by the peripheral; Bluetooth Wacom tablets are widely deployed and an attacker within radio range can present a malicious spoofed Wacom Bluetooth HID device, which is a more severe but reasonable reach path than USB-only scenarios.
- AC:LAttack complexity, low
- The attacker fully controls the malicious device's HID report descriptor and can reliably place HID_DG_INPUTMODE in a non-first field with a high usage_index while keeping field[0]'s report_count small, causing deterministic OOB write during driver initialization without race conditions or rare configuration.
- PR:NPrivileges required, none
- Exploitation requires no privileges on the victim system; an attacker only needs to connect or spoof a malicious Wacom HID peripheral (USB plug-in or Bluetooth advertisement), with no login, capabilities, or user-namespace access required on the target host.
- UI:NUser interaction, none
- No victim interaction with applications or files is needed; the attacker can physically connect a USB device to an unattended machine or deliver a spoofed Bluetooth peripheral, and the kernel automatically parses the descriptor and calls the vulnerable function during device probe or resume.
- S:UScope, unchanged
- The out-of-bounds write corrupts kernel heap memory within the same kernel security boundary, enabling local privilege escalation or denial of service but not crossing a VM, IOMMU, or sandbox boundary.
- C:HConfidentiality impact, high
- The out-of-bounds write to field[0]->value can corrupt adjacent heap objects (new_value, usages_priorities, or neighboring kmalloc allocations), and such kernel heap memory corruption is reasonably exploitable for information disclosure.
- I:HIntegrity impact, high
- This is an out-of-bounds write in kernel heap memory with attacker-influenced offset and value (writes integer 2), which per CVSS kernel guidance constitutes high integrity impact due to potential arbitrary memory corruption and code execution.
- A:HAvailability impact, high
- Corrupting kernel heap metadata or adjacent objects during device initialization can cause kernel oops, panic, or hang, and any out-of-bounds write in kernel space carries high availability impact even before full exploitation.