CVE-2026-52984

What the bug is

The queue limit check in netem_enqueue() uses q->t_len which only counts packets in the internal tfifo. Packets placed in sch->q by the reorder path (__qdisc_enqueue_head) are not counted, allowing the total queue occupancy to exceed sch->limit under reordering. Include sch->q.qlen in the limit check.

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/sched/sch_netem.c

What this is

NETEM NETWORK EMULATORMAINTAINERS section matched on net/sched/sch_netem.c · netdev@vger.kernel.org · Maintained

Kernel module

sch_netem

Check it on the machine

grep -w CONFIG_NET_SCH_NETEM /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 sch_netem

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 as a loadable module. Every release below compiles it as a module on every flavour, so whether the code is in the running kernel depends on whether that module is loaded.

• bookworm, trixie, forky, sidm

m

a loadable module on every flavour - check lsmod, can be blacklisted

Build switch

CONFIG_NET_SCH_NETEM

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

0.13%, higher than 2.2% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

net/sched

Upstream fixes

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

Introduced	Fixed in	Commit
5.10.232	5.10.258	0f875d52db4c
5.15.175	5.15.209	ef9a41b3870f
6.1.121	6.1.175	74fcd8e12720
6.6.67	6.6.141	39a66e83ea41
6.12.6	6.12.91	54b5dbacd00d
6.13	6.18.33	8450462eaf91
6.13	7.0.10	936a7dd87251
6.13	7.1	4185701fcce6
5.4.288	0	0

Debian advisories