CVE-2023-4623

2023-09-0600:00:00

ubuntu.com

linux kernel

local privilege escalation

use-after-free

hfsc qdisc

traffic control

0.0004 Low

EPSS

Percentile

5.2%

JSON

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.

Bugs

Notes

Author	Note
	Priority reason: allows local privilege escalation
sbeattie	might require CAP_NET_ADMIN in the init namespace to set up sch_hfsc scheduler

OSVersionArchitecturePackageVersionFilename
ubuntu18.04noarchlinux< 4.15.0-219.230) Available with Ubuntu Pro or Ubuntu Pro (Infra-onlyUNKNOWN
ubuntu20.04noarchlinux< 5.4.0-165.182UNKNOWN
ubuntu22.04noarchlinux< 5.15.0-87.97UNKNOWN
ubuntu23.04noarchlinux< 6.2.0-35.35UNKNOWN
ubuntu14.04noarchlinux< 3.13.0-194.245) Available with Ubuntu Pro or Ubuntu Pro (Infra-onlyUNKNOWN
ubuntu16.04noarchlinux< 4.4.0-246.280) Available with Ubuntu Pro or Ubuntu Pro (Infra-onlyUNKNOWN
ubuntu18.04noarchlinux-aws< 4.15.0-1162.175) Available with Ubuntu Pro or Ubuntu Pro (Infra-onlyUNKNOWN
ubuntu20.04noarchlinux-aws< 5.4.0-1112.121UNKNOWN
ubuntu22.04noarchlinux-aws< 5.15.0-1048.53UNKNOWN
ubuntu23.04noarchlinux-aws< 6.2.0-1014.14UNKNOWN

OS	Version	Architecture	Package	Version	Filename
ubuntu	18.04	noarch	linux	< 4.15.0-219.230) Available with Ubuntu Pro or Ubuntu Pro (Infra-only	UNKNOWN
ubuntu	20.04	noarch	linux	< 5.4.0-165.182	UNKNOWN
ubuntu	22.04	noarch	linux	< 5.15.0-87.97	UNKNOWN
ubuntu	23.04	noarch	linux	< 6.2.0-35.35	UNKNOWN
ubuntu	14.04	noarch	linux	< 3.13.0-194.245) Available with Ubuntu Pro or Ubuntu Pro (Infra-only	UNKNOWN
ubuntu	16.04	noarch	linux	< 4.4.0-246.280) Available with Ubuntu Pro or Ubuntu Pro (Infra-only	UNKNOWN
ubuntu	18.04	noarch	linux-aws	< 4.15.0-1162.175) Available with Ubuntu Pro or Ubuntu Pro (Infra-only	UNKNOWN
ubuntu	20.04	noarch	linux-aws	< 5.4.0-1112.121	UNKNOWN
ubuntu	22.04	noarch	linux-aws	< 5.15.0-1048.53	UNKNOWN
ubuntu	23.04	noarch	linux-aws	< 6.2.0-1014.14	UNKNOWN