CVE-2023-4623: Use-after-free in Linux kernel's net/sched: sch_hfsc (HFSC qdisc traffic control) component

Modified

AliasesSUSE-SU-2023:4164-1SUSE-SU-2023:4204-1SUSE-SU-2023:4208-1+9 more

Published 06-09-2023Last modified 14-10-2026

Vulnerability summary

CVE-2023-4623 is a high (CVSS 7.8) Use After Free vulnerability in debian debian_linux. EPSS estimates a 0.28% chance of exploitation in the next 30 days, higher than 20.9% of scored vulnerabilities.

Priority

Routine

Not severe (CVSS 7.8, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?

CVSS score

7.8/10

010

High · v3.1 (CVE.org)

EPSS score

0.28%

0%100%

Low · 0.00 pp in 30 days

KEVNot listedNot listed by any tracked catalog.

RansomwareNot flaggedNo ransomware use recorded.

Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 84 · Related 56

DLA-3623-1 DLA-3710-1 LSN-0099-1 OPENSUSE-SU-2024:13305-1 OPENSUSE-SU-2024:13704-1 RHSA-2024:0340+78 more

Timeline

06-09-2023
PublishedVulnerability first disclosed.
14-10-2026
Last modifiedVulnerability information updated.

Description

A use-after-free vulnerability in the Linux kernel's net/sched: sch_hfsc (HFSC qdisc traffic control) component can be exploited to achieve local privilege escalation. If a class with a link-sharing curve (i.e. with the HFSC_FSC flag set) has a parent without a link-sharing curve, then init_vf() will call vttree_insert() on the parent, but vttree_remove() will be skipped in update_vf(). This leaves a dangling pointer that can cause a use-after-free. We recommend upgrading past commit b3d26c5702c7d6c45456326e56d2ccf3f103e60f.

CVSS metrics

5 scores · 5 sources · 1 version

v3.17.8

EPSS trend

Probability

0.28%

Chance of exploitation in the next 30 days

Percentile

21%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.28% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs

CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

CWE-416Use After FreeThe product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

Affected systems

Version check

Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu106 products

linux< 3.13.0-194.245 | < 4.4.0-246.280 | < 4.15.0-219.230 | < 5.4.0-165.182 | < 5.15.0-87.97
linux-allwinner-5.19All versions (No fix recorded)
linux-aws< 4.4.0-1124.130 | < 4.4.0-1162.177 | < 4.15.0-1162.175 | < 5.4.0-1112.121 | < 5.15.0-1048.53
linux-aws-5.0All versions (No fix recorded)
linux-aws-5.11All versions (No fix recorded)

linux-aws-5.13All versions (No fix recorded)
linux-aws-5.15< 5.15.0-1048.53~20.04.1
linux-aws-5.19All versions (No fix recorded)
linux-aws-5.3All versions (No fix recorded)
linux-aws-5.4< 5.4.0-1112.121~18.04.2
linux-aws-5.8All versions (No fix recorded)
linux-aws-6.2< 6.2.0-1014.14~22.04.1
linux-aws-fips< 4.15.0-2101.107 | All versions (No fix recorded) | < 5.4.0-1112.121+fips1
linux-aws-hwe< 4.15.0-1162.175~16.04.1
linux-azure< 4.15.0-1171.186~14.04.1 | < 4.15.0-1171.186~16.04.1 | All versions (No fix recorded) | < 5.4.0-1118.125 | < 5.15.0-1050.57
linux-azure-4.15< 4.15.0-1171.186
linux-azure-5.11All versions (No fix recorded)
linux-azure-5.13All versions (No fix recorded)
linux-azure-5.15< 5.15.0-1050.57~20.04.1
linux-azure-5.19All versions (No fix recorded)
linux-azure-5.3All versions (No fix recorded)
linux-azure-5.4< 5.4.0-1118.125~18.04.1
linux-azure-5.8All versions (No fix recorded)
linux-azure-6.2< 6.2.0-1015.15~22.04.1
linux-azure-edgeAll versions (No fix recorded)
linux-azure-fdeAll versions (No fix recorded) | < 5.15.0-1050.57.1
linux-azure-fde-5.19All versions (No fix recorded)
linux-azure-fips< 4.15.0-2080.86 | All versions (No fix recorded) | < 5.4.0-1118.125+fips1
linux-bluefield< 5.4.0-1073.79 | < 5.15.0-1028.30
linux-fips< 4.4.0-1094.101 | All versions (No fix recorded) | < 4.15.0-1117.128 | < 5.4.0-1087.96
linux-gcp< 4.15.0-1156.173~16.04.1 | All versions (No fix recorded) | < 5.4.0-1116.125 | < 5.15.0-1045.53
linux-gcp-4.15< 4.15.0-1156.173
linux-gcp-5.11All versions (No fix recorded)
linux-gcp-5.13All versions (No fix recorded)
linux-gcp-5.15< 5.15.0-1045.53~20.04.2
linux-gcp-5.19All versions (No fix recorded)
linux-gcp-5.3All versions (No fix recorded)
linux-gcp-5.4< 5.4.0-1116.125~18.04.1
linux-gcp-5.8All versions (No fix recorded)
linux-gcp-6.2< 6.2.0-1017.19~22.04.1
linux-gcp-fips< 4.15.0-2064.69 | All versions (No fix recorded) | < 5.4.0-1116.125+fips1
linux-gkeAll versions (No fix recorded) | < 5.15.0-1045.50
linux-gke-4.15All versions (No fix recorded)
linux-gke-5.15All versions (No fix recorded)
linux-gke-5.4All versions (No fix recorded)
linux-gkeop< 5.4.0-1079.83 | < 5.15.0-1031.37
linux-gkeop-5.15< 5.15.0-1031.37~20.04.1
linux-gkeop-5.4All versions (No fix recorded)
linux-hwe< 4.15.0-219.230~16.04.1 | All versions (No fix recorded)
linux-hwe-5.11All versions (No fix recorded)
linux-hwe-5.13All versions (No fix recorded)
linux-hwe-5.15< 5.15.0-87.97~20.04.1
linux-hwe-5.19All versions (No fix recorded)
linux-hwe-5.4< 5.4.0-165.182~18.04.1
linux-hwe-5.8All versions (No fix recorded)
linux-hwe-6.2< 6.2.0-35.35~22.04.1
linux-hwe-edgeAll versions (No fix recorded)
linux-ibm< 5.4.0-1059.64 | < 5.15.0-1041.44
linux-ibm-5.15< 5.15.0-1041.44~20.04.1
linux-ibm-5.4< 5.4.0-1059.64~18.04.1
linux-intel-5.13All versions (No fix recorded)
linux-intel-iot-realtime< 5.15.0-1041.43
linux-intel-iotg< 5.15.0-1043.49
linux-intel-iotg-5.15< 5.15.0-1043.49~20.04.1
linux-iot< 5.4.0-1024.25
linux-kvm< 4.4.0-1125.135 | < 4.15.0-1146.151 | < 5.4.0-1101.107 | < 5.15.0-1045.50
linux-lowlatency< 5.15.0-87.96
linux-lowlatency-hwe-5.15< 5.15.0-87.96~20.04.1
linux-lowlatency-hwe-5.19All versions (No fix recorded)
linux-lowlatency-hwe-6.2< 6.2.0-1015.15~22.04.1
linux-lts-xenial< 4.4.0-246.280~14.04.1
linux-nvidia< 5.15.0-1039.39
linux-nvidia-6.2< 6.2.0-1011.11
linux-nvidia-tegra< 5.15.0-1019.19
linux-nvidia-tegra-5.15< 5.15.0-1019.19~20.04.1
linux-nvidia-tegra-igx< 5.15.0-1006.6
linux-oemAll versions (No fix recorded)
linux-oem-5.10All versions (No fix recorded)
linux-oem-5.13All versions (No fix recorded)
linux-oem-5.14All versions (No fix recorded)
linux-oem-5.17All versions (No fix recorded)
linux-oem-5.6All versions (No fix recorded)
linux-oem-6.0All versions (No fix recorded)
linux-oem-6.1< 6.1.0-1023.23
linux-oem-6.5< 6.5.0-1004.4
linux-oracle< 4.15.0-1125.136~16.04.1 | < 4.15.0-1125.136 | < 5.4.0-1111.120 | < 5.15.0-1046.52
linux-oracle-5.0All versions (No fix recorded)
linux-oracle-5.11All versions (No fix recorded)
linux-oracle-5.13All versions (No fix recorded)
linux-oracle-5.15< 5.15.0-1046.52~20.04.1
linux-oracle-5.3All versions (No fix recorded)
linux-oracle-5.4< 5.4.0-1111.120~18.04.1
linux-oracle-5.8All versions (No fix recorded)
linux-raspi< 5.4.0-1096.107 | < 5.15.0-1041.44
linux-raspi-5.4< 5.4.0-1096.107~18.04.1
linux-raspi-realtimeAll versions (No fix recorded)
linux-raspi2All versions (No fix recorded)
linux-realtimeAll versions (No fix recorded) | < 5.15.0-1049.55
linux-riscvAll versions (No fix recorded)
linux-riscv-5.11All versions (No fix recorded)
linux-riscv-5.15< 5.15.0-1044.48~20.04.1
linux-riscv-5.19All versions (No fix recorded)
linux-riscv-5.8All versions (No fix recorded)
linux-starfive-5.19All versions (No fix recorded)
linux-starfive-6.2< 6.2.0-1007.8~22.04.1
linux-xilinx-zynqmp< 5.4.0-1032.36 | < 5.15.0-1025.29

Show all 106

Redhat18 products

bpftool< 0:3.10.0-957.112.1.el7
kernel< 0:3.10.0-957.112.1.el7
kernel-abi-whitelists< 0:3.10.0-957.112.1.el7
kernel-debug< 0:3.10.0-957.112.1.el7
kernel-debug-debuginfo< 0:3.10.0-957.112.1.el7

Show all 18

Suse15 products

kernel-livepatch-SLE15-SP1_Update_35&distro=SUSE Linux Enterprise Live Patching 15 SP1< 12-150100.2.3
kernel-livepatch-SLE15-SP1_Update_36&distro=SUSE Linux Enterprise Live Patching 15 SP1< 10-150100.2.3
kernel-livepatch-SLE15-SP1_Update_41&distro=SUSE Linux Enterprise Live Patching 15 SP1< 5-150100.2.2
kernel-livepatch-SLE15-SP1_Update_42&distro=SUSE Linux Enterprise Live Patching 15 SP1< 4-150100.2.2
kernel-livepatch-SLE15-SP2_Update_39&distro=SUSE Linux Enterprise Live Patching 15 SP2< 3-150200.2.1

Show all 15

Debian2 products

linux< 6.1.55-1 | < 6.5.3-1
debian_linuxEOL10.0

Linux2 products

kernel≥ 2.6.12, < 6.6
linux_kernel≥ 2.6.12, < 4.14.327 | ≥ 4.15, < 4.19.295 | ≥ 4.20, < 5.4.257 | ≥ 5.5, < 5.10.195 | ≥ 5.11, < 5.15.132 | ≥ 5.16, < 6.1.53 | ≥ 6.2, < 6.4.16 | ≥ 6.5, < 6.5.3

5 vendors · 143 products