CVE-2023-4921

Name	CVE-2023-4921
Description	A use-after-free vulnerability in the Linux kernel's net/sched: sch_qfq component can be exploited to achieve local privilege escalation. When the plug qdisc is used as a class of the qfq qdisc, sending network packets triggers use-after-free in qfq_dequeue() due to the incorrect .peek handler of sch_plug and lack of error checking in agg_dequeue(). We recommend upgrading past commit 8fc134fee27f2263988ae38920bc03da416b03d8.
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
linux (PTS)	buster	4.19.249-2	vulnerable
	buster (security)	4.19.289-2	vulnerable
	bullseye	5.10.178-3	vulnerable
	bullseye (security)	5.10.191-1	vulnerable
	bookworm	6.1.38-1	vulnerable
	bookworm (security)	6.1.52-1	vulnerable
	sid, trixie	6.5.3-1	vulnerable

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
linux	source	(unstable)	(unfixed)

https://kernel.dance/#8fc134fee27f2263988ae38920bc03da416b03d8
https://git.kernel.org/linus/8fc134fee27f2263988ae38920bc03da416b03d8 (6.6-rc1)