CVE-2026-64174

What the bug is

cfg80211_merge_profile() reassembles a Multi-BSSID non-transmitted BSS profile that has been split across multiple consecutive MBSSID elements. Its while-loop calls cfg80211_get_profile_continuation(ie, ielen, mbssid_elem, sub_elem) but never advances mbssid_elem or sub_elem inside the body. Each iteration therefore searches for a continuation that follows the same fixed pair; the helper returns the same next_mbssid; and the same next_sub bytes are memcpy()'d into merged_ie at a growing offset until the buffer fills. Advance both mbssid_elem and sub_elem to the just-consumed continuation so the next call to cfg80211_get_profile_continuation() searches for a further continuation beyond it (or returns NULL when none exists). A specially-crafted malicious beacon can take advantage of this bug to cause the kernel to spend an excessive amount of time in cfg80211_merge_profile (up to as much as 2ms per beacon received), which could theoretically be abused in some way.

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/wireless/scan.c

What this is

802.11 (including CFG80211/NL80211)MAINTAINERS section matched on net/wireless/ · linux-wireless@vger.kernel.org · Maintained

Kernel module

cfg80211

Check it on the machine

grep -wE 'CONFIG_CFG80211|CONFIG_WIRELESS' /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 cfg80211

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.

• bookwormMnot built on amd64/cloud-amd64, arm64/cloud-arm64
• trixie, forky, sidMnot built on amd64/cloud-amd64, arm64/cloud-arm64, s390x/s390x

M

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

Build switches

CONFIG_CFG80211, CONFIG_WIRELESS

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

2026-07-19 (3 months ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.12%, higher than 1.7% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

net/wireless

Upstream fixes

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

Introduced	Fixed in	Commit
5.2	5.10.258	5817e1e52054
5.2	5.15.209	cedbb608494b
5.2	6.1.175	c0bc4c8bd556
5.2	6.6.142	1ced0f5a851f
5.2	6.12.92	67915715fd38
5.2	6.18.34	6cfae4914439
5.2	7.0.11	1343a480f84b
5.2	7.1	7666dbb1bacc