CVE-2023-4623

NameCVE-2023-4623
DescriptionA 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.
SourceCVE (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 PackageReleaseVersionStatus
linux (PTS)buster4.19.249-2vulnerable
buster (security)4.19.289-2vulnerable
bullseye5.10.178-3vulnerable
bullseye (security)5.10.191-1vulnerable
bookworm6.1.38-1vulnerable
bookworm (security)6.1.52-1vulnerable
sid, trixie6.5.3-1fixed

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
linuxsource(unstable)6.5.3-1

Notes

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

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