🛡️ CVE-2023-4206 on Debian — linux

⚪ Unknown ✅ No Known Exploit OSV
N/A
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

A use-after-free vulnerability in the Linux kernel's net/sched: cls_route component can be exploited to achieve local privilege escalation. When route4_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 b80b829e9e2c1b3f7aae34855e04d8f6ecaf13c8.

Distribution advisory

This page covers CVE-2023-4206 as tracked by Debian, for the package linux. The fix is available in version 6.4.11-1; earlier versions remain affected.

How this vulnerability can be exploited

This issue can be reached with local access to the system, attack complexity is low, an attacker needs low-level privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability high.

Weakness class

DEBIAN-CVE-2023-4206 is classified as CWE-416: Use After Free. Memory is used after being released, so its contents may already belong to something else.

Affected software

DEBIAN-CVE-2023-4206 is recorded against 1 package.

  • linux (fixed in 6.4.11-1)

Timeline and source

Published on 6 September 2023 and last revised on 7 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

security-tracker.debian.org (Advisory)

CVE-2023-4206 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity Unknown
CVSS Score N/A
CVSS Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2023-09-06
Updated 2026-08-12
Modified 2026-08-07
Fix URL N/A

Affected Packages

Software From version Fixed in
linux — 6.4.11-1

Similar Threats

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