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CVE-2026-93826
HID: hidpp: fix potential UAF in hidpp_connect_event()
Published 2026-09-24 (24 days 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-2026-93826 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 | fixedDLA-4841-1 · 2026-10-17 · text | 6.1.190-1 | Update the kernel and reboot. DLA-4841-1 shipped the fix on 2026-10-17, in 6.1.190-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixedDSA-6528-1 · 2026-09-29 · text | 6.12.111-1 | Update the kernel and reboot. DSA-6528-1 shipped the fix on 2026-09-29, in 6.12.111-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.2.6-1 | Update the kernel and reboot. Fixed in 7.2.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.2.6-1 | Update the kernel and reboot. Fixed in 7.2.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4817-1 · 2026-10-04 · text | 6.12.111-1~deb12u1 | Update the kernel and reboot. DLA-4817-1 shipped the fix on 2026-10-04, in 6.12.111-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
If input_register_device() fails, we call input_free_device(), but keep stale pointer to the old device in hidpp->input, which could potentially lead to UAF. Fix that by resetting it to NULL before returning from hidpp_connect_event().
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/hid-logitech-hidpp.c
- What this is
- HID++ LOGITECH DRIVERSMAINTAINERS section matched on drivers/hid/hid-logitech-hidpp.c · linux-input@vger.kernel.org · Maintained
- Kernel module
- hid_logitech_hidpp
Check it on the machine
grep -wE 'CONFIG_HID|CONFIG_HID_LOGITECH_HIDPP|CONFIG_HID_SUPPORT' /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 hid_logitech_hidppPrints 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, sid, bookworm · linux-6.12Mnot 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_LOGITECH_HIDPP, CONFIG_HID_SUPPORT
- 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
- 2026-09-24 (24 days ago)source
- CVSS
- 7.5 high
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- adjacent network (AV:A)source
- EPSS
- 0.23%, higher than 13.3% 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 |
|---|---|---|
| 3.19 | 6.1.189 | e03fd646adad |
| 3.19 | 6.6.158 | 5d7637f4d050 |
| 3.19 | 6.12.111 | 3b8b2e58b078 |
| 3.19 | 6.18.53 | 3303398cc2aa |
| 3.19 | 7.2 | 6df6b1f2c496 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4841-1 | 2026-10-17 | bookworm 6.1.190-1 | tracker |
| DLA-4817-1 | 2026-10-04 | bookworm 6.12.111-1~deb12u1 | tracker |
| DSA-6528-1 | 2026-09-29 | trixie 6.12.111-1 | tracker |
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 UAF is in hidpp_connect_event(), reached from hidpp_probe() and from hidpp_raw_hidpp_event() on a HID++ short report with rap.sub_id 0x41. DELAYED_INIT devices are Unifying DJ children (PIDs 0x4011/0x4101/0x402d via logi_dj_recv_add_djhid_device) and Bluetooth T651, so the trigger arrives over Unifying 2.4 GHz or Bluetooth HIDP.
- AC:HAttack complexity, high
- The dangling hidpp->input is created only when hidpp_populate_input() stores the new device and input_register_device() then fails, so hidpp_connect_event() calls input_free_device() without clearing the pointer. That register fails on GFP_KERNEL ENOMEM (devres_alloc/input_device_tune_vals), device_add(), or -EINTR on input_mutex, which a HID++ peer cannot induce on demand.
- PR:NPrivileges required, none
- logi_dj_raw_event() delivers Unifying pairing/connect notifications and HID++ reports to the child with no host credential check, and hidpp_probe() binds logitech-hidpp-device during that enumeration; Bluetooth T651 HIDP bind is likewise unauthenticated. No OS account or capability is required.
- UI:NUser interaction, none
- A REPORT_TYPE_NOTIF_DEVICE_PAIRED/CONNECTED notification (or T651 HIDP connect) runs hidpp_probe() which schedules hidpp_connect_event(); after the failed register, later HID reports handled by wtp_raw_event()/m560_raw_event() dereference hidpp->input. The attacker's peripheral generates both without a victim mount, click, or prompt.
- S:UScope, unchanged
- The freed object is the delayed struct input_dev allocated by hidpp_allocate_input() and stored in hidpp->input; the UAF stays inside the host kernel HID/input authority and does not cross a VM, IOMMU, or sandbox boundary.
- C:HConfidentiality impact, high
- After input_free_device(), wtp_raw_event()/m560_raw_event() still see a non-NULL hidpp->input and call input_mt_get_slot_by_key()/input_event()/input_sync() on the freed input_dev (vals, absinfo, mt slots). UAF of that heap object is an arbitrary-read primitive once the slab is reused.
- I:HIntegrity impact, high
- The same dangling hidpp->input is used for input_mt_slot(), input_report_key/rel(), and input_sync(), which write event state and walk handlers on the freed input_dev; heap spray of that object yields arbitrary kernel writes and control-flow hijack.
- A:HAvailability impact, high
- Dereferencing the freed input_dev in wtp_touch_event()/m560_raw_event() after hidpp_connect_event()'s input_free_device() oopses or panics when the object is not reused; hidpp_probe() still succeeds, and DJ's no-op logi_dj_ll_close() keeps delivering reports that retrigger the crash.