CVE-2023-4921
Use-after-free in Linux kernel's net/sched: sch_qfq component
CVSS Score
7.8
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-416 |
| Vendor | linux |
| Product | kernel |
| Ecosystems | |
| Industries | Technology |
| Published | Sep 12, 2023 |
| Last Updated | Feb 25, 2026 |
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CVSS v3 Breakdown
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
Affected Versions
Linux / Kernel
3.8 < 6.6
References
git.kernel.org: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=8fc134fee27f2263988ae38920bc03da416b03d8 kernel.dance: https://kernel.dance/8fc134fee27f2263988ae38920bc03da416b03d8 lists.debian.org: https://lists.debian.org/debian-lts-announce/2023/10/msg00027.html lists.debian.org: https://lists.debian.org/debian-lts-announce/2024/01/msg00004.html
Credits
valis