CVE-2023-4623
Public on 2023-09-06
Modified on 2024-04-22
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.
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.
Severity
Important
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 |
| NVD | CVSSv3 | 7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |