CVE-2026-80799

What the bug is

nfc_llcp_parse_gb_tlv() and nfc_llcp_parse_connection_tlv() contain three related bugs in their TLV parsing loops: 1. 'offset' is declared u8 but tlv_array_len is u16. When TLV data advances offset past 255 it silently wraps to zero, causing infinite loops or double-processing of buffer data. 2. Before reading tlv[0] (type) and tlv[1] (length) there is no check that offset+2 <= tlv_array_len. A truncated TLV causes an OOB read of one byte past the buffer end. 3. After reading the length field, the value bytes are accessed without checking offset+2+length <= tlv_array_len. A crafted length=0xFF on a short buffer causes up to 255 bytes of OOB read past the buffer end. Both functions are reachable without authentication via nfc_llcp_set_remote_gb() which feeds remote LLCP general bytes directly into nfc_llcp_parse_gb_tlv() with no additional validation. Fix all three issues by widening offset from u8 to u16 and adding bounds checks for both the TLV header and value field before each access.

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.

net/nfc/llcp_commands.c

What this is

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

Kernel module

nfc

Check it on the machine

grep -w CONFIG_NFC /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 nfc

Prints 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 switch

CONFIG_NFC

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

0.23%, higher than 13.3% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

net/nfc

Upstream fixes

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

Introduced	Fixed in	Commit
5.10.188	5.10.267	2c1456fe09ab
5.15	5.15.218	7f6f3d087c67
5.15	6.1.185	9c47d6679635
5.15	6.6.154	a209334ed929
5.15	6.12.106	382eaa770335
5.15	6.18.47	2d239590d184
5.15	7.1.11	e84cdfdc4a6c
5.15	7.2.1	875285a165fd
5.15	7.3	78b20c8eeacd
4.19.291	0	0
5.4.251	0	0

Debian advisories