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TI-2023-04532 Aliases CVE-2023-4921GHSA-qw4m-2pv2-7r5f

Use-after-free in Linux kernel's net/sched: sch_qfq component

Priority LOW 36CWE-416Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-416 and the CVSS impact.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00419 36th percentileScored 2026-11-07
Public exploit Yes 2 exploit referencesTagged by NVD
Fix Fixed Kernel (Linux): 6.6Red Hat: 19 advisories

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxKernel3.8 to before 6.66.6Patch availableCNA
  • Kernel VendorLinux Affected 3.8 to before 6.6 Fixed in 6.6 Patch available CNA

CPE configurations NVD · 2

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*3.8 to before 4.14.326; 4.15 to before 4.19.295; 4.20 to before 5.4.257; 5.5 to before 5.10.195; 5.11 to before 5.15.132; 5.16 to before 6.1.54; 6.2 to before 6.5.4VulnerableLinux
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*10.0VulnerableDebian
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 3.8 to before 4.14.326; 4.15 to before 4.19.295; 4.20 to before 5.4.257; 5.5 to before 5.10.195; 5.11 to before 5.15.132; 5.16 to before 6.1.54; 6.2 to before 6.5.4 Vulnerable ·Linux
  • cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* Versions 10.0 Vulnerable ·Debian

Remediation

  • Fix · CNA Kernel (Linux) Fixed in 6.6

Red Hat 19 advisories

  • RHSA-2024:1831 Released 2024-04-16 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux Server (v. 6 ELS) kernel-2.6.32-754.53.1.el6, kernel-abi-whitelists-2.6.32-754.53.1.el6, kernel-debug-2.6.32-754.53.1.el6 +7
    • Red Hat Enterprise Linux Server Optional (v. 6 ELS) python-perf-2.6.32-754.53.1.el6
  • RHSA-2024:1404 Released 2024-03-19 · Red Hat rating Important
    kernel security and bug fix update
    • Red Hat CodeReady Linux Builder EUS (v.8.8) kernel-tools-libs-devel-4.18.0-477.51.1.el8_8
    • Red Hat Enterprise Linux BaseOS EUS (v.8.8) bpftool-4.18.0-477.51.1.el8_8, kernel-4.18.0-477.51.1.el8_8, kernel-abi-stablelists-4.18.0-477.51.1.el8_8 +19
  • RHSA-2024:1368 Released 2024-03-19 · Red Hat rating Important
    kpatch-patch security update
    • Red Hat Enterprise Linux BaseOS EUS (v.8.8) kpatch-patch-4_18_0-477_27_1-1-3.el8_8, kpatch-patch-4_18_0-477_36_1-1-2.el8_8, kpatch-patch-4_18_0-477_43_1-1-1.el8_8
Show 16 more Red Hat advisories
  • RHSA-2024:1332 Released 2024-03-14 · Red Hat rating Important
    kernel-rt security update
    • Red Hat Enterprise Linux for Real Time (v. 7) kernel-rt-3.10.0-1160.114.2.rt56.1266.el7, kernel-rt-debug-3.10.0-1160.114.2.rt56.1266.el7, kernel-rt-debug-devel-3.10.0-1160.114.2.rt56.1266.el7 +4
    • Red Hat Enterprise Linux for Real Time for NFV (v. 7) kernel-rt-3.10.0-1160.114.2.rt56.1266.el7, kernel-rt-debug-3.10.0-1160.114.2.rt56.1266.el7, kernel-rt-debug-devel-3.10.0-1160.114.2.rt56.1266.el7 +7
  • RHSA-2024:1323 Released 2024-03-13 · Red Hat rating Important
    kpatch-patch security update
    • Red Hat Enterprise Linux Server (v. 7) kpatch-patch-3_10_0-1160_102_1-1-3.el7, kpatch-patch-3_10_0-1160_105_1-1-2.el7, kpatch-patch-3_10_0-1160_108_1-1-1.el7 +1
  • RHSA-2024:1278 Released 2024-03-12 · Red Hat rating Important
    kpatch-patch security update
    • Red Hat Enterprise Linux BaseOS E4S (v. 8.2) kpatch-patch-4_18_0-193_113_1-1-4.el8_2, kpatch-patch-4_18_0-193_116_1-1-3.el8_2, kpatch-patch-4_18_0-193_119_1-1-2.el8_2 +1
  • RHSA-2024:1269 Released 2024-03-12 · Red Hat rating Important
    kernel-rt security update
    • Red Hat Enterprise Linux Real Time TUS (v. 8.2) kernel-rt-4.18.0-193.128.1.rt13.179.el8_2, kernel-rt-core-4.18.0-193.128.1.rt13.179.el8_2, kernel-rt-debug-4.18.0-193.128.1.rt13.179.el8_2 +7
    • Red Hat Enterprise Linux Real Time for NFV TUS (v. 8.2) kernel-rt-4.18.0-193.128.1.rt13.179.el8_2, kernel-rt-core-4.18.0-193.128.1.rt13.179.el8_2, kernel-rt-debug-4.18.0-193.128.1.rt13.179.el8_2 +9
  • RHSA-2024:1268 Released 2024-03-12 · Red Hat rating Important
    kernel security and bug fix update
    • Red Hat Enterprise Linux BaseOS AUS (v. 8.2) bpftool-4.18.0-193.128.1.el8_2, kernel-4.18.0-193.128.1.el8_2, kernel-abi-whitelists-4.18.0-193.128.1.el8_2 +14
    • Red Hat Enterprise Linux BaseOS E4S (v. 8.2) bpftool-4.18.0-193.128.1.el8_2, kernel-4.18.0-193.128.1.el8_2, kernel-abi-whitelists-4.18.0-193.128.1.el8_2 +14
    • Red Hat Enterprise Linux BaseOS TUS (v. 8.2) bpftool-4.18.0-193.128.1.el8_2, kernel-4.18.0-193.128.1.el8_2, kernel-abi-whitelists-4.18.0-193.128.1.el8_2 +14
  • RHSA-2024:1249 Released 2024-03-12 · Red Hat rating Important
    kernel security and bug fix update
    • Red Hat Enterprise Linux Client (v. 7) bpftool-3.10.0-1160.114.2.el7, kernel-3.10.0-1160.114.2.el7, kernel-abi-whitelists-3.10.0-1160.114.2.el7 +8
    • Red Hat Enterprise Linux Client Optional (v. 7) kernel-tools-libs-devel-3.10.0-1160.114.2.el7
    • Red Hat Enterprise Linux ComputeNode Optional (v. 7) kernel-tools-libs-devel-3.10.0-1160.114.2.el7
    • Red Hat Enterprise Linux Server (v. 7) bpftool-3.10.0-1160.114.2.el7, kernel-3.10.0-1160.114.2.el7, kernel-abi-whitelists-3.10.0-1160.114.2.el7 +11
    • Red Hat Enterprise Linux Server Optional (v. 7) kernel-debug-devel-3.10.0-1160.114.2.el7, kernel-tools-libs-devel-3.10.0-1160.114.2.el7
    • Red Hat Enterprise Linux Workstation (v. 7) bpftool-3.10.0-1160.114.2.el7, kernel-3.10.0-1160.114.2.el7, kernel-abi-whitelists-3.10.0-1160.114.2.el7 +8
    • Red Hat Enterprise Linux Workstation Optional (v. 7) kernel-tools-libs-devel-3.10.0-1160.114.2.el7
  • RHSA-2024:0999 Released 2024-02-27 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux Server AUS (v. 7.7) bpftool-3.10.0-1062.85.1.el7, kernel-3.10.0-1062.85.1.el7, kernel-abi-whitelists-3.10.0-1062.85.1.el7 +8
    • Red Hat Enterprise Linux Server Optional AUS (v. 7.7) kernel-tools-libs-devel-3.10.0-1062.85.1.el7
  • RHSA-2024:0980 Released 2024-02-26 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux Server AUS (v. 7.6) bpftool-3.10.0-957.111.1.el7, kernel-3.10.0-957.111.1.el7, kernel-abi-whitelists-3.10.0-957.111.1.el7 +8
    • Red Hat Enterprise Linux Server Optional AUS (v. 7.6) kernel-tools-libs-devel-3.10.0-957.111.1.el7
  • RHSA-2024:0897 Released 2024-02-20 · Red Hat rating Important
    kernel security update
    • Red Hat CodeReady Linux Builder (v. 8) kernel-tools-libs-devel-4.18.0-513.18.1.el8_9
    • Red Hat Enterprise Linux BaseOS (v. 8) bpftool-4.18.0-513.18.1.el8_9, kernel-4.18.0-513.18.1.el8_9, kernel-abi-stablelists-4.18.0-513.18.1.el8_9 +19
  • RHSA-2024:0881 Released 2024-02-20 · Red Hat rating Important
    kernel-rt security update
    • Red Hat Enterprise Linux Real Time for NFV (v. 8) kernel-rt-4.18.0-513.18.1.rt7.320.el8_9, kernel-rt-core-4.18.0-513.18.1.rt7.320.el8_9, kernel-rt-debug-4.18.0-513.18.1.rt7.320.el8_9 +9
    • Red Hat Enterprise Linux for Real Time (v. 8) kernel-rt-4.18.0-513.18.1.rt7.320.el8_9, kernel-rt-core-4.18.0-513.18.1.rt7.320.el8_9, kernel-rt-debug-4.18.0-513.18.1.rt7.320.el8_9 +7
  • RHSA-2024:0876 Released 2024-02-20 · Red Hat rating Important
    kpatch-patch security update
    • Red Hat Enterprise Linux BaseOS (v. 8) kpatch-patch-4_18_0-513_11_1-1-1.el8_9, kpatch-patch-4_18_0-513_5_1-1-3.el8_9, kpatch-patch-4_18_0-513_9_1-1-2.el8_9
  • RHSA-2024:0851 Released 2024-02-15 · Red Hat rating Important
    kpatch-patch security update
    • Red Hat Enterprise Linux BaseOS EUS (v.8.6) kpatch-patch-4_18_0-372_64_1-1-5.el8_6, kpatch-patch-4_18_0-372_70_1-1-4.el8_6, kpatch-patch-4_18_0-372_75_1-1-3.el8_6 +2
  • RHSA-2024:0724 Released 2024-02-07 · Red Hat rating Important
    kernel security and bug fix update
    • Red Hat CodeReady Linux Builder EUS (v.8.6) kernel-tools-libs-devel-4.18.0-372.91.1.el8_6
    • Red Hat Enterprise Linux BaseOS EUS (v.8.6) bpftool-4.18.0-372.91.1.el8_6, kernel-4.18.0-372.91.1.el8_6, kernel-abi-stablelists-4.18.0-372.91.1.el8_6 +19
    • Red Hat Virtualization 4 Hypervisor for RHEL 8 kernel-devel-4.18.0-372.91.1.el8_6, perf-4.18.0-372.91.1.el8_6
  • RHSA-2024:0593 Released 2024-01-30 · Red Hat rating Important
    kpatch-patch security update
    • Red Hat Enterprise Linux BaseOS E4S (v.8.4) kpatch-patch-4_18_0-305_103_1-1-3.el8_4, kpatch-patch-4_18_0-305_108_1-1-2.el8_4, kpatch-patch-4_18_0-305_114_1-1-1.el8_4 +1
  • RHSA-2024:0562 Released 2024-01-30 · Red Hat rating Important
    kernel security and bug fix update
    • Red Hat Enterprise Linux BaseOS AUS (v.8.4) bpftool-4.18.0-305.120.1.el8_4, kernel-4.18.0-305.120.1.el8_4, kernel-abi-stablelists-4.18.0-305.120.1.el8_4 +14
    • Red Hat Enterprise Linux BaseOS E4S (v.8.4) bpftool-4.18.0-305.120.1.el8_4, kernel-4.18.0-305.120.1.el8_4, kernel-abi-stablelists-4.18.0-305.120.1.el8_4 +14
    • Red Hat Enterprise Linux BaseOS TUS (v.8.4) bpftool-4.18.0-305.120.1.el8_4, kernel-4.18.0-305.120.1.el8_4, kernel-abi-stablelists-4.18.0-305.120.1.el8_4 +14
  • RHSA-2024:0563 Released 2024-01-30 · Red Hat rating Important
    kernel-rt security update
    • Red Hat Enterprise Linux NFV TUS (v.8.4) kernel-rt-4.18.0-305.120.1.rt7.196.el8_4, kernel-rt-core-4.18.0-305.120.1.rt7.196.el8_4, kernel-rt-debug-4.18.0-305.120.1.rt7.196.el8_4 +9
    • Red Hat Enterprise Linux RT TUS (v.8.4) kernel-rt-4.18.0-305.120.1.rt7.196.el8_4, kernel-rt-core-4.18.0-305.120.1.rt7.196.el8_4, kernel-rt-debug-4.18.0-305.120.1.rt7.196.el8_4 +7

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat CodeReady Linux Builder (v. 8)Fixed RHSA-2024:0897
Red Hat CodeReady Linux Builder EUS (v.8.6)Fixed RHSA-2024:0724
Red Hat CodeReady Linux Builder EUS (v.8.8)Fixed RHSA-2024:1404
Red Hat Enterprise Linux BaseOS (v. 8)Fixed RHSA-2024:0876, RHSA-2024:0897
Red Hat Enterprise Linux BaseOS AUS (v. 8.2)Fixed RHSA-2024:1268
Red Hat Enterprise Linux BaseOS AUS (v.8.4)Fixed RHSA-2024:0562
Red Hat Enterprise Linux BaseOS E4S (v. 8.2)Fixed RHSA-2024:1268, RHSA-2024:1278
Red Hat Enterprise Linux BaseOS E4S (v.8.4)Fixed RHSA-2024:0562, RHSA-2024:0593
Red Hat Enterprise Linux BaseOS EUS (v.8.6)Fixed RHSA-2024:0724, RHSA-2024:0851
Red Hat Enterprise Linux BaseOS EUS (v.8.8)Fixed RHSA-2024:1368, RHSA-2024:1404
Red Hat Enterprise Linux BaseOS TUS (v. 8.2)Fixed RHSA-2024:1268
Red Hat Enterprise Linux BaseOS TUS (v.8.4)Fixed RHSA-2024:0562
Red Hat Enterprise Linux Client (v. 7)Fixed RHSA-2024:1249
Red Hat Enterprise Linux Client Optional (v. 7)Fixed RHSA-2024:1249
Red Hat Enterprise Linux ComputeNode Optional (v. 7)Fixed RHSA-2024:1249
Red Hat Enterprise Linux NFV TUS (v.8.4)Fixed RHSA-2024:0563
Red Hat Enterprise Linux RT TUS (v.8.4)Fixed RHSA-2024:0563
Red Hat Enterprise Linux Real Time TUS (v. 8.2)Fixed RHSA-2024:1269
Red Hat Enterprise Linux Real Time for NFV (v. 8)Fixed RHSA-2024:0881
Red Hat Enterprise Linux Real Time for NFV TUS (v. 8.2)Fixed RHSA-2024:1269
Red Hat Enterprise Linux Server (v. 6 ELS)Fixed RHSA-2024:1831
Red Hat Enterprise Linux Server (v. 7)Fixed RHSA-2024:1249, RHSA-2024:1323
Red Hat Enterprise Linux Server AUS (v. 7.6)Fixed RHSA-2024:0980
Red Hat Enterprise Linux Server AUS (v. 7.7)Fixed RHSA-2024:0999
Red Hat Enterprise Linux Server Optional (v. 6 ELS)Fixed RHSA-2024:1831
Red Hat Enterprise Linux Server Optional (v. 7)Fixed RHSA-2024:1249
Red Hat Enterprise Linux Server Optional AUS (v. 7.6)Fixed RHSA-2024:0980
Red Hat Enterprise Linux Server Optional AUS (v. 7.7)Fixed RHSA-2024:0999
Red Hat Enterprise Linux Workstation (v. 7)Fixed RHSA-2024:1249
Red Hat Enterprise Linux Workstation Optional (v. 7)Fixed RHSA-2024:1249
Red Hat Enterprise Linux for Real Time (v. 7)Fixed RHSA-2024:1332
Red Hat Enterprise Linux for Real Time (v. 8)Fixed RHSA-2024:0881
Red Hat Enterprise Linux for Real Time for NFV (v. 7)Fixed RHSA-2024:1332
Red Hat Virtualization 4 Hypervisor for RHEL 8Fixed RHSA-2024:0724
Not affected: 1 product
  • Red Hat Enterprise Linux 9

Timeline

  1. 2026-10-02 Threatist record created from CVE-2023-4921
  2. 2026-10-03 Alias added: GHSA-qw4m-2pv2-7r5f

References

Exploit 2

Advisory 2

  • TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
  • TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
  • TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
  • TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
  • TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
See all 15278 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences