Use After Free Affecting kernel-libbpf package, versions <0:6.1.55-75.123.amzn2023


Severity

Recommended
0.0
high
0
10

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.04% (6th percentile)

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  • Snyk IDSNYK-AMZN2023-KERNELLIBBPF-5927754
  • published4 Oct 2023
  • disclosed6 Sept 2023

Introduced: 6 Sep 2023

CVE-2023-4623  (opens in a new tab)
CWE-416  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 kernel-libbpf to version 0:6.1.55-75.123.amzn2023 or higher.
This issue was patched in ALAS2023-2023-356.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-libbpf package and not the kernel-libbpf package as distributed by Amazon-Linux. See How to fix? for Amazon-Linux:2023 relevant fixed versions and status.

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.

CVSS Scores

version 3.1