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CVE-2026-80569
Input: synaptics-rmi4 - bound the F54 report size to the allocated buffer
Published 2026-08-26 (2 months ago) by the Linux kernel CNA. Subsystem drivers/input. Debian urgency: not yet assigned.
Debian does not build this code. The per-release build detail is under "Where it lives" below.
What to do, per Debian release
Debian's own status for CVE-2026-80569 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-4777-1 · 2026-09-08 · text | 6.1.187-1 | Update the kernel and reboot. DLA-4777-1 shipped the fix on 2026-09-08, in 6.1.187-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixed | 6.12.105-1 | Update the kernel and reboot. Fixed in 6.12.105-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.1.10-1 | Update the kernel and reboot. Fixed in 7.1.10-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.10-1 | Update the kernel and reboot. Fixed in 7.1.10-1. A running kernel keeps the old code until the machine restarts. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4788-1 · 2026-09-19 · text | 6.12.107-1~deb12u1 | Update the kernel and reboot. DLA-4788-1 shipped the fix on 2026-09-19, in 6.12.107-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
rmi_f54_work() reads a diagnostics report from the device into f54->report_data, sizing the transfer with rmi_f54_get_report_size(): report_size = rmi_f54_get_report_size(f54); ... for (i = 0; i < report_size; i += F54_REPORT_DATA_SIZE) { int size = min(F54_REPORT_DATA_SIZE, report_size - i); ... rmi_read_block(.., f54->report_data + i, size); } report_data is allocated once at probe from F54's own electrode counts (array3_size(f54->num_tx_electrodes, f54->num_rx_electrodes, sizeof(u16))), but rmi_f54_get_report_size() computes the size from drv_data->num_*_electrodes when those are set, i.e. from the F55 function's electrode counts. Both counts come straight from device queries (F54 and F55 each report up to 255 electrodes) and nothing constrains the F55 counts to the F54 ones. A malicious or malfunctioning RMI4 device that reports larger F55 electrode counts than its F54 counts makes report_size exceed the allocation, so the read loop writes past report_data (and the V4L2 dequeue memcpy() then reads past it). On conforming hardware the F55 configured electrodes are a subset of the F54 physical electrodes, so report_size never exceeds the buffer and well-behaved devices are unaffected. Record the allocation size and reject a report that does not fit, mirroring the existing zero-size check.
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/input/rmi4/rmi_f54.c
- What this is
- INPUT (KEYBOARD, MOUSE, JOYSTICK, TOUCHSCREEN) DRIVERSMAINTAINERS section matched on drivers/input/ · linux-input@vger.kernel.org · Maintained
- Kernel module
- none to look for. The file would have gone into rmi_core, and Debian does not compile it into that module, so finding rmi_core in lsmod would say nothing about this CVE.
Check it on the machine
grep -wE 'CONFIG_INPUT|CONFIG_RMI4_CORE|CONFIG_RMI4_F54' /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.
Show whether Debian builds this, per release
Debian does not build this code. In 5 releases below, every kernel flavour Debian publishes has the switch off, so the vulnerable file is compiled into no kernel binary Debian ships.
- bookworm, trixie, forky, sid, bookworm · linux-6.12n
- n
- not enabled on any flavour - this release does not build the code
- Build switches
- CONFIG_INPUT, CONFIG_RMI4_CORE, CONFIG_RMI4_F54
- 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
- 2026-08-26 (2 months ago)source
- CVSS
- 7.8 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.12%, higher than 1.7% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- drivers/input
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 4.10 | 5.10.266 | 6b3bdd44d4cd |
| 4.10 | 5.15.217 | b2f596f00d27 |
| 4.10 | 6.1.184 | b3932101c9c4 |
| 4.10 | 6.6.153 | 12be3c6ca958 |
| 4.10 | 6.12.105 | 42eaf0e6f79c |
| 4.10 | 6.18.46 | 6b06aab79ff1 |
| 4.10 | 7.1.10 | b7b9a8b1c303 |
| 4.10 | 7.2 | 49c5adc2b7d6 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4788-1 | 2026-09-19 | bookworm 6.12.107-1~deb12u1 | tracker |
| DLA-4777-1 | 2026-09-08 | bookworm 6.1.187-1 | 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:LAttack vector, local
- Exploitation is reached through local V4L2 ioctls on the synaptics-rmi4 F54 touch diagnostics video node (/dev/video*); streaming a report drives rmi_f54_buffer_queue() into rmi_f54_work(), which performs the unchecked copy. A malicious on-bus RMI4 device is the precondition, but the syscall path is Local.
- AC:LAttack complexity, low
- After probe with mismatched F54/F55 electrode counts, an attacker with access to the V4L2 node can select a 16-bit report type and queue buffers to deterministically trigger a multi-kilobyte heap overflow; no race or fragile layout assumptions are required beyond device-reported sizes.
- PR:LPrivileges required, low
- Triggering the overflow requires only permission to open the registered VFL_TYPE_TOUCH video device and issue standard V4L2 capture ioctls; no CAP_SYS_ADMIN or root capability is needed where seat/session policy grants video or input device access to an unprivileged local user.
- UI:NUser interaction, none
- No victim interaction is required beyond the attacker opening the diagnostics node and starting capture; no other user must mount filesystems, plug devices, or perform cooperative actions at exploit time.
- S:UScope, unchanged
- Impact is confined to host kernel memory within the same security boundary; this is a kernel heap corruption in the input driver and does not inherently provide VM escape, IOMMU bypass, or cross-sandbox authority change.
- C:HConfidentiality impact, high
- rmi_f54_work() performs an out-of-bounds write past devm-allocated report_data, and rmi_f54_buffer_queue() memcpy() can read past that buffer into the userspace capture buffer, leaking adjacent kmalloc/slab contents including potentially sensitive kernel pointers.
- I:HIntegrity impact, high
- The device-driven read loop writes up to roughly 130 KiB past report_data (255x255x2 minus the F54-sized allocation), supplying attacker-influenced report bytes that can corrupt adjacent heap objects and enable control-flow hijacking or privilege escalation primitives.
- A:HAvailability impact, high
- Corrupting adjacent slab memory via the out-of-bounds write can immediately panic or oops the kernel; the overflow is repeatable on each queued V4L2 buffer while the mismatched device remains present.