CVE-2026-53082

What the bug is

sixpack_receive_buf() does not properly skip bytes with TTY error flags. The while loop iterates through the flags buffer but never advances the data pointer (cp), and passes the original count (including error bytes) to sixpack_decode(). This causes sixpack_decode() to process bytes that should have been skipped due to TTY errors. The TTY layer does not guarantee that cp[i] holds a meaningful value when fp[i] is set, so passing those positions to sixpack_decode() results in KMSAN reporting an uninit-value read. Fix this by processing bytes one at a time, advancing cp on each iteration, and only passing valid (non-error) bytes to sixpack_decode(). This matches the pattern used by slip_receive_buf() and mkiss_receive_buf() for the same purpose.

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/net/hamradio/6pack.c

What this is

NETWORKING DRIVERSMAINTAINERS section matched on drivers/net/ · netdev@vger.kernel.org · Maintained

Kernel module

6pack

Check it on the machine

grep -wE 'CONFIG_6PACK|CONFIG_HAMRADIO' /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 6pack

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. The build rule could not be established for 2 releases, so nothing is claimed about those.

• bookworm, trixieMnot built on amd64/cloud-amd64, arm64/cloud-arm64
• forky, sid?

M

a module where it is built at all; some flavours do not build it

?

not established - no Makefile entry for the affected file

Where a release above reads "not established", no build rule for the affected file was found in that release's kernel tree. That is a gap in this lookup, not a finding that the code is absent.

Build switches

CONFIG_6PACK, CONFIG_HAMRADIO

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

2026-06-24 (4 months ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.16%, higher than 5.1% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

drivers/net

Upstream fixes

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

Introduced	Fixed in	Commit
2.6.12	5.10.258	1d3abf0c3dde
2.6.12	5.15.209	d4cceb518453
2.6.12	6.1.175	2951656b0de0
2.6.12	6.6.141	e9cf4018d742
2.6.12	6.12.91	d9ce2a4b6791
2.6.12	6.18.33	987af7625ceb
2.6.12	7.0.10	578f3aba427c
2.6.12	7.1	bf9a38803b26

Debian advisories