CVE-2026-98483

What the bug is

Commit 6709d4b7bc2e ("net: nfc: Fix use-after-free caused by nfc_llcp_find_local") attempted to fix a use-after-free (UAF) issue by invoking nfc_llcp_local_put(local) after accessing local->gb. However, if the reference count drops to zero, local is freed immediately, leading to a use-after-free when callers access the returned pointer. Alternative approaches using dynamic allocation (e.g. kmemdup) introduced memory leaks because callers consistently treat the returned pointer as borrowed memory. Fix this properly by refactoring nfc_llcp_general_bytes() and nfc_get_local_general_bytes() to accept a caller-provided output buffer (out_gb) and its maximum length (gb_max_len). The general bytes are safely copied into out_gb before calling nfc_llcp_local_put(local), ensuring safe lifetime management without ownership transfer complications. Update all callers across drivers (microread, pn533, pn544, st21nfca, digital_dep, and nci) to provide their own destination buffers and pass them to nfc_get_local_general_bytes().

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/microread/microread.c
drivers/nfc/pn533/pn533.c
drivers/nfc/pn533/pn533.h
drivers/nfc/pn544/pn544.c
drivers/nfc/st21nfca/core.c
include/net/nfc/hci.h
include/net/nfc/nfc.h
net/nfc/core.c
net/nfc/digital_dep.c
net/nfc/llcp_core.c
net/nfc/nci/core.c
net/nfc/nfc.h

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 microread, and Debian does not compile it into that module, so finding microread in lsmod would say nothing about this CVE.

Check it on the machine

grep -w CONFIG_NFC_MICROREAD /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 4 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, sidn

n

not enabled on any flavour - this release does not build the code

Build switch

CONFIG_NFC_MICROREAD

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

2026-10-18 (today)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

not scored

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
5.10.188	5.10.271	25bfa673adc7
5.15.121	5.15.222	2b31d0cc9585
6.1.39	6.1.189	c40f61a6a413
6.5	6.6.158	19bcfc2a56d0
6.5	6.12.112	d8c929e9afdb
6.5	6.18.55	841af260ff47
6.5	7.2.9	9ede11e12f96
6.5	7.3	dcab71a70119
5.4.251	0	0
6.3.13	0	0
6.4.4	0	0