CVE-2026-80802

What the bug is

fdp_nci_i2c_read() takes the next packet length from two device-supplied bytes and never validates it. The value is a u16 used as the i2c_master_recv() count into a 261-byte on-stack buffer: a malicious, counterfeit or malfunctioning controller (or an i2c bus interposer) can drive it far past the buffer for a stack out-of-bounds write that clobbers the canary and return address, or below the minimum frame size (directly, or by truncating the computed sum) so the header/LRC strip and the next length read run past a short receive. Reject a length outside [FDP_NCI_I2C_MIN_PAYLOAD, FDP_NCI_I2C_MAX_PAYLOAD], as a corrupted packet already is, and force resynchronization. The same loop allocates one data skb per iteration and assumes a length packet followed by a data packet; a device that sends two data packets in one call leaks the first skb when the second allocation overwrites it. Free a previously allocated skb before allocating the next.

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/nfc/fdp/i2c.c

What this is

NFC SUBSYSTEMMAINTAINERS section matched on drivers/nfc/ · oe-linux-nfc@lists.linux.dev · Maintained

Kernel module

none to look for. The file would have gone into fdp_i2c, and Debian does not compile it into that module, so finding fdp_i2c in lsmod would say nothing about this CVE.

Check it on the machine

grep -wE 'CONFIG_NFC_FDP|CONFIG_NFC_FDP_I2C' /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_NFC_FDP, CONFIG_NFC_FDP_I2C

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

2026-09-04 (44 days ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.24%, higher than 14.4% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

drivers/nfc

Upstream fixes

The versions the CNA records as introducing and fixing this, and the commit for each. source

Introduced	Fixed in	Commit
4.4	5.10.267	d9498ab9a78c
4.4	5.15.218	1fc32327b927
4.4	6.1.185	8d2c243b7985
4.4	6.6.154	fc3c2bd5b1ec
4.4	6.12.106	0d723090645b
4.4	6.18.47	db7e464b3509
4.4	7.1.11	e5eec121f2c3
4.4	7.2.1	1aa3fc769b0c
4.4	7.3	7ad21dcfeb51

Debian advisories