Public on 2023-09-06
Modified on 2024-01-12
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.
Important severity
CVSS v3 Base Score
See breakdown

Affected Packages

Platform Package Release Date Advisory Status
Amazon Linux 1 kernel 2023-09-27 ALAS-2023-1838 Fixed
Amazon Linux 2 - Core kernel 2023-09-27 ALAS2-2023-2264 Fixed
Amazon Linux 2 - Kernel-5.10 Extra kernel 2023-09-27 ALAS2KERNEL-5.10-2023-040 Fixed
Amazon Linux 2 - Kernel-5.15 Extra kernel 2023-09-27 ALAS2KERNEL-5.15-2023-027 Fixed
Amazon Linux 2 - Kernel-5.4 Extra kernel 2023-09-27 ALAS2KERNEL-5.4-2023-053 Fixed
Amazon Linux 2023 kernel 2023-09-27 ALAS2023-2023-356 Fixed
Amazon Linux 2 - Livepatch Extra kernel-livepatch-4.14.320-243.544 2023-10-31 ALAS2LIVEPATCH-2023-154 Fixed
Amazon Linux 2 - Livepatch Extra kernel-livepatch-4.14.322-244.536 2023-10-31 ALAS2LIVEPATCH-2023-152 Fixed
Amazon Linux 2 - Livepatch Extra kernel-livepatch-4.14.322-244.539 2023-10-31 ALAS2LIVEPATCH-2023-153 Fixed
Amazon Linux 2 - Livepatch Extra kernel-livepatch-4.14.322-246.539 2023-10-31 ALAS2LIVEPATCH-2023-151 Fixed
Amazon Linux 2 - Livepatch Extra kernel-livepatch-5.10.186-179.751 2023-10-31 ALAS2LIVEPATCH-2023-155 Fixed
Amazon Linux 2 - Livepatch Extra kernel-livepatch-5.10.192-182.736 2023-10-31 ALAS2LIVEPATCH-2023-150 Fixed
Amazon Linux 2 - Livepatch Extra kernel-livepatch-5.10.192-183.736 2023-10-31 ALAS2LIVEPATCH-2023-149 Fixed
Amazon Linux 2023 kernel-livepatch-6.1.49-69.116 2023-12-06 ALAS2023LIVEPATCH-2023-025 Fixed
Amazon Linux 2023 kernel-livepatch-6.1.49-70.116 2023-12-06 ALAS2023LIVEPATCH-2023-026 Fixed
Amazon Linux 2023 kernel-livepatch-6.1.52-71.125 2023-12-06 ALAS2023LIVEPATCH-2023-024 Fixed

CVSS Scores

Score Type Score Vector
Amazon Linux CVSSv3 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H