CVE-2023-4921Use-after-free in Linux kernel's net/sched: sch_qfq component
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It affects Linux Kernel and 6 other products. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- CWE-416
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- NVD analysis
- Modified
- Record last updated
- Oct 14, 2026
- First seen by InfoSec Signals
- Oct 14, 2026
Affected products
Linux Kernel linux:kernel (from the name) | from 3.8 before 6.6 | CNA record |
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518_4_pn_dp_mfp (from the name) | from V3.1.0 before V3.1.5 | CISA ADP |
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518f_4_pn_dp_mfp (from the name) | from V3.1.0 before V3.1.5 | CISA ADP |
Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem siemens:simatic_s7_1500_tm_mfp_gnu_linux_subsystem (from the name) | before V1.1 | CISA ADP |
Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP siemens:siplus_s7_1500_cpu_1518_4_pn_dp_mfp (from the name) | from V3.1.0 before V3.1.5 | CISA ADP |
linux linux_kernel linux:linux_kernel | from 3.8 before 4.14.326; from 4.15 before 4.19.295; from 4.20 before 5.4.257; from 5.5 before 5.10.195; from 5.11 before 5.15.132; from 5.16 before 6.1.54; from 6.2 before 6.5.4 | NVD |
debian debian_linux debian:debian_linux | 10.0 | NVD |
References
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=8fc134fee27f2263988ae38920bc03da416b03d8patch, exploit, mailing-list, vendor-advisory
- https://kernel.dance/8fc134fee27f2263988ae38920bc03da416b03d8exploit, patch, vendor-advisory
- https://lists.debian.org/debian-lts-announce/2023/10/msg00027.htmlmailing-list, third-party-advisory
- https://lists.debian.org/debian-lts-announce/2024/01/msg00004.htmlmailing-list, third-party-advisory
- https://cert-portal.siemens.com/productcert/html/ssa-398330.html
- https://cert-portal.siemens.com/productcert/html/ssa-769027.html
- https://cert-portal.siemens.com/productcert/html/ssa-794697.html
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.