vulnerability

Oracle Linux: CVE-2023-4208: ELSA-2023-12970: Unbreakable Enterprise kernel security update (IMPORTANT) (Multiple Advisories)

Severity
7
CVSS
(AV:L/AC:L/Au:S/C:C/I:C/A:C)
Published
Jul 29, 2023
Added
Nov 3, 2023
Modified
Dec 3, 2025

Description

A use-after-free vulnerability in the Linux kernel's net/sched: cls_u32 component can be exploited to achieve local privilege escalation.
When u32_change() is called on an existing filter, the whole tcf_result struct is always copied into the new instance of the filter. This causes a problem when updating a filter bound to a class, as tcf_unbind_filter() is always called on the old instance in the success path, decreasing filter_cnt of the still referenced class and allowing it to be deleted, leading to a use-after-free.
We recommend upgrading past commit 3044b16e7c6fe5d24b1cdbcf1bd0a9d92d1ebd81.
There are 3 CVEs for the use-after-free flaw found in net/sched/cls_fw.c in classifiers (cls_fw, cls_u32, and cls_route) in the Linux Kernel: CVE-2023-4206, CVE-2023-4207, CVE-2023-4208.
A local user could use any of these flaws to crash the system or potentially escalate their privileges on the system.
Similar CVE-2023-4128 was rejected as a duplicate.

Solutions

oracle-linux-upgrade-kerneloracle-linux-upgrade-kernel-uek
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