CVE-2023-4623

Name	CVE-2023-4623
Description	A use-after-free vulnerability in the Linux kernel's net/sched: sch_hfsc (HFSC qdisc traffic control) component can be exploited to achieve local privilege escalation. If a class with a link-sharing curve (i.e. with the HFSC_FSC flag set) has a parent without a link-sharing curve, then init_vf() will call vttree_insert() on the parent, but vttree_remove() will be skipped in update_vf(). This leaves a dangling pointer that can cause a use-after-free. We recommend upgrading past commit b3d26c5702c7d6c45456326e56d2ccf3f103e60f.
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	fixed

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
linux	source	(unstable)	6.5.3-1

https://git.kernel.org/linus/b3d26c5702c7d6c45456326e56d2ccf3f103e60f