CVE Database›Document archive›CVE-2023-4921

CVE-2023-4921

kernel: use-after-free in sch_qfq network scheduler

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Severity

Important

Red Hat Product Security

7.8

CVSS 3.1

Review impact separately from score.

Published · September 5, 2023

Updated · October 15, 2026

Description

A use-after-free flaw was found in qfq_dequeue and agg_dequeue in net/sched/sch_qfq.c in the Traffic Control (QoS) subsystem in the Linux kernel. This issue may allow a local user to crash the system or escalate their privileges on the system.

CVSS score applicability

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation

Mitigation for this issue is to skip loading the affected module sch_qfq onto the system until we have a fix available. This can be done by a blacklist mechanism and will ensure the driver is not loaded at the boot time.

 How do I blacklist a kernel module to prevent it from loading automatically? 
https://access.redhat.com/solutions/41278  

CVSS / CWE

CVSS 3.1 · 7.8
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CWE-416 · Use After Free