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CVE-2023-4921

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CVE-2023-4921

Published: Sep 12, 2023

Modified: Feb 25, 2026

PUBLISHED

CVSS v3.1

7.8

HIGH

Description

A use-after-free vulnerability in the Linux kernel's net/sched: sch_qfq component can be exploited to achieve local privilege escalation. When the plug qdisc is used as a class of the qfq qdisc, sending network packets triggers use-after-free in qfq_dequeue() due to the incorrect .peek handler of sch_plug and lack of error checking in agg_dequeue(). We recommend upgrading past commit 8fc134fee27f2263988ae38920bc03da416b03d8.

VendorProductVersions

Linux

Kernel

affected
3.8 - < 6.6

Weaknesses (CWE)

CVSS v3.1 Details

CVSS v3.1 Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

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CVE-2023-4921 | HIGH (7.8) - Security Vulnerability | QwikSec