🛡️ CVE-2023-4623 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: 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.

Distribution advisory

This page covers CVE-2023-4623 as tracked by Debian, for the package linux. The fix is available in version 6.5.3-1; 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-2023-4623 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-2023-4623 is recorded against 1 package.

  • linux (fixed in 6.5.3-1)

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-2023-4623 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 — 6.5.3-1

Similar Threats

Site Security Check

Is linux part of your stack?

DEBIAN-CVE-2023-4623 is rated CVSS 7.8 High. BotEraser scans your installation against known CVE records and tells you whether this vulnerability applies to the versions you actually run.

Scan My Site Free →

No credit card required  ·  Results in minutes

ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

Browse related advisories

All advisoriesDebianDebian 2023