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)
ReferencesDLA-3623-1, DLA-3710-1, ELA-1034-1, ELA-991-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
linux (PTS)jessie, jessie (lts)3.16.84-1vulnerable
stretch (security)4.9.320-2vulnerable
stretch (lts), stretch4.9.320-3vulnerable
buster4.19.249-2vulnerable
buster (security)4.19.304-1fixed
bullseye5.10.209-2fixed
bullseye (security)5.10.216-1fixed
bookworm6.1.76-1fixed
bookworm (security)6.1.90-1fixed
sid, trixie6.7.12-1fixed
linux-4.19 (PTS)jessie, jessie (lts)4.19.304-1~deb8u1fixed
stretch (security)4.19.232-1~deb9u1vulnerable
stretch (lts), stretch4.19.304-1~deb9u1fixed
linux-5.10 (PTS)jessie, jessie (lts)5.10.209-2~deb8u1fixed
stretch (lts), stretch5.10.209-2~deb9u1fixed
buster (security)5.10.216-1~deb10u1fixed

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
linuxsourcejessie(unfixed)end-of-life
linuxsourcestretch(unfixed)end-of-life
linuxsourcebuster4.19.304-1DLA-3710-1
linuxsourcebullseye5.10.197-1
linuxsourcebookworm6.1.55-1
linuxsource(unstable)6.5.3-1
linux-4.19sourcejessie4.19.304-1~deb8u1ELA-1034-1
linux-4.19sourcestretch4.19.304-1~deb9u1ELA-1034-1
linux-5.10sourcejessie5.10.197-1~deb8u1ELA-991-1
linux-5.10sourcestretch5.10.197-1~deb9u1ELA-991-1
linux-5.10sourcebuster5.10.197-1~deb10u1DLA-3623-1

Notes

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

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