CVE-2021-4023

A flaw was found in the io-workqueue implementation in the Linux kernel versions prior to 5.15...

5.5 MediumFix available

A flaw was found in the io-workqueue implementation in the Linux kernel versions prior to 5.15-rc1. The kernel can panic when an improper cancellation operation triggers the submission of new io-uring operations during a shortage of free space. This flaw allows a local user with permissions to execute io-uring requests to possibly crash the system.

Attack profile

How easy it is to exploit

Attack vector: Local
Complexity: Low
Privileges needed: Low
User interaction: None

What an attacker can affect

Confidentiality: None
Integrity: None
Availability: High

Exploit likelihood

0.24%Down 0.6 points since Mar 10, 2022

What each source reports

NVD Score used 5.5

Record: CVE-2021-4023
CVSS 3.1: 5.5 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CVSS 2.0: 4.9 MediumAV:L/AC:L/Au:N/C:N/I:N/A:C
Weakness: CWE-200
Updated: 2026-11-02

CVE List No score

Record: CVE-2021-4023
Weakness: CWE-200
Updated: 2026-11-02

EUVDEUVD-2021-33926 No score

Record: EUVD-2021-33926
Updated: 2026-11-03

GitHub AdvisoriesGHSA-rfvh-hg5j-x539 5.5

A flaw was found in the io-workqueue implementation in the Linux kernel versions prior to 5.15...

Record: GHSA-rfvh-hg5j-x539
CVSS 3.1: 5.5 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

OSV 5.5

Record: CVE-2021-4023
CVSS 3.1: 5.5 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

OSVDEBIAN-CVE-2021-4023 5.5

Record: DEBIAN-CVE-2021-4023
CVSS 3.1: 5.5 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

OSVUBUNTU-CVE-2021-4023 5.5

Record: UBUNTU-CVE-2021-4023
CVSS 3.1: 5.5 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

OSVROOT-OS-DEBIAN-11-CVE-2021-4023 No score

CVE-2021-4023 in linux - Patched by Root

Root has patched CVE-2021-4023 in the linux package for Root:Debian:11. Multiple fixed versions available.

Record: ROOT-OS-DEBIAN-11-CVE-2021-4023
Updated: 2026-11-02

Affected products

Affected packages

Affected packages
Package	Affected	Fixed
`linux` Debian:12	before 5.15.3-1	5.15.3-1
`linux` Debian:13	before 5.15.3-1	5.15.3-1
`linux` Debian:14	before 5.15.3-1	5.15.3-1
`linux` Root:Debian:11	before 5.10.262-1.aikido.113	5.10.262-1.aikido.1135.10.262-1.aikido.114
`rootio-linux` Root:Debian:11	before 5.10.262-1.aikido.113	5.10.262-1.aikido.1135.10.262-1.aikido.114
`linux-hwe-edge` Ubuntu:16.04:LTS	All versions, plus listed versions 4.8.0-28.30~16.04.14.8.0-30.32~16.04.14.8.0-32.34~16.04.14.8.0-34.36~16.04.14.10.0-14.16~16.04.1 Show 18 moreShow less 4.10.0-19.21~16.04.14.10.0-20.22~16.04.14.10.0-21.23~16.04.14.10.0-22.24~16.04.14.10.0-24.28~16.04.14.10.0-26.30~16.04.14.11.0-13.19~16.04.14.11.0-14.20~16.04.14.13.0-16.19~16.04.34.13.0-17.20~16.04.14.13.0-19.22~16.04.14.13.0-21.24~16.04.14.13.0-25.29~16.04.24.15.0-13.14~16.04.14.15.0-15.16~16.04.14.15.0-20.21~16.04.14.15.0-22.24~16.04.14.15.0-23.25~16.04.1	None known
`linux-aws-5.0` Ubuntu:18.04:LTS	All versions, plus listed versions 5.0.0-1021.24~18.04.15.0.0-1022.25~18.04.15.0.0-1023.26~18.04.15.0.0-1024.27~18.04.15.0.0-1025.285.0.0-1027.30	None known
`linux-aws-5.3` Ubuntu:18.04:LTS	All versions, plus listed versions 5.3.0-1016.17~18.04.15.3.0-1017.18~18.04.15.3.0-1019.21~18.04.15.3.0-1023.25~18.04.15.3.0-1028.30~18.04.1 Show 5 moreShow less 5.3.0-1030.32~18.04.15.3.0-1032.34~18.04.25.3.0-1033.355.3.0-1034.365.3.0-1035.37	None known
`linux-azure` Ubuntu:18.04:LTS	All versions, plus listed versions 4.15.0-1002.24.15.0-1003.34.15.0-1004.44.15.0-1008.84.15.0-1009.9 Show 39 moreShow less 4.15.0-1012.124.15.0-1013.134.15.0-1014.144.15.0-1018.184.15.0-1019.194.15.0-1021.214.15.0-1022.234.15.0-1023.244.15.0-1025.264.15.0-1028.294.15.0-1030.314.15.0-1031.324.15.0-1032.334.15.0-1035.364.15.0-1036.384.15.0-1037.394.18.0-1011.11~18.04.14.18.0-1013.13~18.04.14.18.0-1014.14~18.04.14.18.0-1018.18~18.04.14.18.0-1019.19~18.04.14.18.0-1020.20~18.04.14.18.0-1023.24~18.04.14.18.0-1024.25~18.04.14.18.0-1025.27~18.04.15.0.0-1014.14~18.04.15.0.0-1016.17~18.04.15.0.0-1018.19~18.04.15.0.0-1020.21~18.04.15.0.0-1022.23~18.04.15.0.0-1023.24~18.04.15.0.0-1025.27~18.04.15.0.0-1027.29~18.04.15.0.0-1028.30~18.04.15.0.0-1029.31~18.04.15.0.0-1031.335.0.0-1032.345.0.0-1035.375.0.0-1036.38	None known
`linux-azure-5.3` Ubuntu:18.04:LTS	All versions, plus listed versions 5.3.0-1007.8~18.04.15.3.0-1008.9~18.04.15.3.0-1009.10~18.04.15.3.0-1010.11~18.04.15.3.0-1012.13~18.04.1 Show 11 moreShow less 5.3.0-1013.14~18.04.15.3.0-1016.17~18.04.15.3.0-1018.19~18.04.15.3.0-1019.20~18.04.15.3.0-1020.21~18.04.15.3.0-1022.23~18.04.15.3.0-1028.29~18.04.15.3.0-1031.32~18.04.15.3.0-1032.33~18.04.15.3.0-1034.35~18.04.15.3.0-1035.36	None known

Show 20 moreShow less

Affected packages
Package	Affected	Fixed
`linux-azure-edge` Ubuntu:18.04:LTS	All versions, plus listed versions 4.18.0-1006.6~18.04.14.18.0-1007.7~18.04.14.18.0-1008.8~18.04.15.0.0-1012.12~18.04.2	None known
`linux-gcp` Ubuntu:18.04:LTS	All versions, plus listed versions 4.15.0-1001.14.15.0-1003.34.15.0-1005.54.15.0-1006.64.15.0-1008.8 Show 33 moreShow less 4.15.0-1009.94.15.0-1010.104.15.0-1014.144.15.0-1015.154.15.0-1017.184.15.0-1018.194.15.0-1019.204.15.0-1021.224.15.0-1023.244.15.0-1024.254.15.0-1025.264.15.0-1026.274.15.0-1027.284.15.0-1028.294.15.0-1029.314.15.0-1030.324.15.0-1032.344.15.0-1033.354.15.0-1034.364.15.0-1036.384.15.0-1037.394.15.0-1040.424.15.0-1042.454.15.0-1044.705.0.0-1020.20~18.04.15.0.0-1021.21~18.04.15.0.0-1025.26~18.04.15.0.0-1026.27~18.04.15.0.0-1028.29~18.04.15.0.0-1029.30~18.04.15.0.0-1031.325.0.0-1033.345.0.0-1034.35	None known
`linux-gcp-5.3` Ubuntu:18.04:LTS	All versions, plus listed versions 5.3.0-1008.9~18.04.15.3.0-1009.10~18.04.15.3.0-1010.11~18.04.15.3.0-1012.13~18.04.15.3.0-1014.15~18.04.1 Show 8 moreShow less 5.3.0-1016.17~18.04.15.3.0-1017.18~18.04.15.3.0-1018.19~18.04.15.3.0-1020.22~18.04.15.3.0-1026.28~18.04.15.3.0-1029.31~18.04.15.3.0-1030.32~18.04.15.3.0-1032.34~18.04.1	None known
`linux-gke-4.15` Ubuntu:18.04:LTS	All versions, plus listed versions 4.15.0-1030.324.15.0-1032.344.15.0-1033.354.15.0-1034.364.15.0-1036.38 Show 28 moreShow less 4.15.0-1037.394.15.0-1040.424.15.0-1041.434.15.0-1042.444.15.0-1044.464.15.0-1045.484.15.0-1046.494.15.0-1048.514.15.0-1049.524.15.0-1050.534.15.0-1052.554.15.0-1055.584.15.0-1057.604.15.0-1058.614.15.0-1059.624.15.0-1063.664.15.0-1064.674.15.0-1066.694.15.0-1067.704.15.0-1069.724.15.0-1070.734.15.0-1072.764.15.0-1073.784.15.0-1074.794.15.0-1076.814.15.0-1077.824.15.0-1078.834.15.0-1079.84	None known
`linux-hwe` Ubuntu:18.04:LTS	All versions, plus listed versions 4.18.0-13.14~18.04.14.18.0-14.15~18.04.14.18.0-15.16~18.04.14.18.0-16.17~18.04.14.18.0-17.18~18.04.1 Show 38 moreShow less 4.18.0-18.19~18.04.14.18.0-20.21~18.04.14.18.0-21.22~18.04.14.18.0-22.23~18.04.14.18.0-24.25~18.04.14.18.0-25.26~18.04.15.0.0-23.24~18.04.15.0.0-25.26~18.04.15.0.0-27.28~18.04.15.0.0-29.31~18.04.15.0.0-31.33~18.04.15.0.0-32.34~18.04.25.0.0-35.38~18.04.15.0.0-36.39~18.04.15.0.0-37.40~18.04.15.3.0-26.28~18.04.15.3.0-28.30~18.04.15.3.0-40.32~18.04.15.3.0-42.34~18.04.15.3.0-45.37~18.04.15.3.0-46.38~18.04.15.3.0-51.44~18.04.25.3.0-53.47~18.04.15.3.0-59.53~18.04.15.3.0-61.55~18.04.15.3.0-62.56~18.04.15.3.0-64.58~18.04.15.3.0-65.595.3.0-66.605.3.0-67.615.3.0-68.635.3.0-69.655.3.0-70.665.3.0-72.685.3.0-73.695.3.0-74.705.3.0-75.715.3.0-76.72	None known
`linux-hwe-edge` Ubuntu:18.04:LTS	All versions, plus listed versions 5.0.0-15.16~18.04.15.0.0-16.17~18.04.15.0.0-17.18~18.04.15.0.0-19.20~18.04.15.0.0-20.21~18.04.1 Show 5 moreShow less 5.3.0-19.20~18.04.25.3.0-22.24~18.04.15.3.0-23.25~18.04.15.3.0-23.25~18.04.25.3.0-24.26~18.04.2	None known
`linux-oem` Ubuntu:18.04:LTS	All versions, plus listed versions 4.15.0-1002.34.15.0-1004.54.15.0-1006.94.15.0-1008.114.15.0-1009.12 Show 45 moreShow less 4.15.0-1012.154.15.0-1013.164.15.0-1015.184.15.0-1017.204.15.0-1018.214.15.0-1021.244.15.0-1024.294.15.0-1026.314.15.0-1028.334.15.0-1030.354.15.0-1033.384.15.0-1034.394.15.0-1035.404.15.0-1036.414.15.0-1038.434.15.0-1039.444.15.0-1043.484.15.0-1045.504.15.0-1050.574.15.0-1056.654.15.0-1057.664.15.0-1059.684.15.0-1063.724.15.0-1064.734.15.0-1065.754.15.0-1066.764.15.0-1067.774.15.0-1069.794.15.0-1073.834.15.0-1076.864.15.0-1079.894.15.0-1080.904.15.0-1081.914.15.0-1087.974.15.0-1090.1004.15.0-1091.1014.15.0-1093.1034.15.0-1094.1044.15.0-1096.1064.15.0-1097.1074.15.0-1099.1094.15.0-1100.1104.15.0-1101.1124.15.0-1102.1134.15.0-1103.114	None known
`linux-oracle-5.0` Ubuntu:18.04:LTS	All versions, plus listed versions 5.0.0-1007.12~18.04.15.0.0-1008.13~18.04.15.0.0-1009.14~18.04.15.0.0-1010.15~18.04.15.0.0-1011.165.0.0-1013.185.0.0-1014.19	None known
`linux-oracle-5.3` Ubuntu:18.04:LTS	All versions, plus listed versions 5.3.0-1011.12~18.04.15.3.0-1013.14~18.04.15.3.0-1014.15~18.04.15.3.0-1016.18~18.04.15.3.0-1018.20~18.04.1 Show 4 moreShow less 5.3.0-1024.26~18.04.15.3.0-1027.29~18.04.15.3.0-1028.30~18.04.15.3.0-1030.32~18.04.1	None known
`linux-aws-5.8` Ubuntu:20.04:LTS	All versions, plus listed versions 5.8.0-1035.37~20.04.15.8.0-1038.40~20.04.15.8.0-1041.43~20.04.15.8.0-1042.44~20.04.1	None known
`linux-azure-5.8` Ubuntu:20.04:LTS	All versions, plus listed versions 5.8.0-1033.35~20.04.15.8.0-1036.38~20.04.15.8.0-1039.42~20.04.15.8.0-1040.43~20.04.15.8.0-1041.44~20.04.15.8.0-1042.45~20.04.15.8.0-1043.46~20.04.1	None known
`linux-gcp-5.8` Ubuntu:20.04:LTS	All versions, plus listed versions 5.8.0-1032.34~20.04.15.8.0-1035.37~20.04.15.8.0-1038.40~20.04.15.8.0-1039.41	None known
`linux-hwe-5.11` Ubuntu:20.04:LTS	All versions, plus listed versions 5.11.0-22.23~20.04.15.11.0-25.27~20.04.15.11.0-27.29~20.04.15.11.0-34.36~20.04.15.11.0-36.40~20.04.1 Show 7 moreShow less 5.11.0-37.41~20.04.25.11.0-38.42~20.04.15.11.0-40.44~20.04.25.11.0-41.45~20.04.15.11.0-43.47~20.04.25.11.0-44.48~20.04.25.11.0-46.51~20.04.1	None known
`linux-hwe-5.8` Ubuntu:20.04:LTS	All versions, plus listed versions 5.8.0-23.24~20.04.15.8.0-25.26~20.04.15.8.0-28.30~20.04.15.8.0-29.31~20.04.15.8.0-31.33~20.04.1 Show 16 moreShow less 5.8.0-33.36~20.04.15.8.0-34.37~20.04.25.8.0-36.40~20.04.15.8.0-38.43~20.04.15.8.0-40.45~20.04.15.8.0-41.46~20.04.15.8.0-43.49~20.04.15.8.0-44.50~20.04.15.8.0-45.51~20.04.15.8.0-48.54~20.04.15.8.0-49.55~20.04.15.8.0-50.56~20.04.15.8.0-53.60~20.04.15.8.0-55.62~20.04.15.8.0-59.66~20.04.15.8.0-63.71~20.04.1	None known
`linux-intel-5.13` Ubuntu:20.04:LTS	All versions, plus listed versions 5.13.0-1007.75.13.0-1008.85.13.0-1009.95.13.0-1010.105.13.0-1011.115.13.0-1014.155.13.0-1017.19	None known
`linux-oem-5.6` Ubuntu:20.04:LTS	All versions, plus listed versions 5.6.0-1007.75.6.0-1008.85.6.0-1010.105.6.0-1011.115.6.0-1013.13 Show 24 moreShow less 5.6.0-1017.175.6.0-1018.185.6.0-1020.205.6.0-1021.215.6.0-1023.235.6.0-1026.265.6.0-1027.275.6.0-1028.285.6.0-1031.325.6.0-1032.335.6.0-1033.355.6.0-1034.365.6.0-1035.375.6.0-1036.395.6.0-1039.435.6.0-1042.465.6.0-1047.515.6.0-1048.525.6.0-1050.545.6.0-1052.565.6.0-1053.575.6.0-1054.585.6.0-1055.595.6.0-1056.60	None known
`linux-oracle-5.8` Ubuntu:20.04:LTS	All versions, plus listed versions 5.8.0-1031.32~20.04.25.8.0-1033.34~20.04.15.8.0-1034.35~20.04.25.8.0-1037.38~20.04.15.8.0-1038.39~20.04.1	None known
`linux-raspi2` Ubuntu:20.04:LTS	All versions, plus listed versions 5.3.0-1007.85.3.0-1014.165.3.0-1015.175.3.0-1017.195.4.0-1004.45.4.0-1006.6	None known
`linux-riscv` Ubuntu:20.04:LTS	All versions, plus listed versions 5.4.0-24.285.4.0-26.305.4.0-27.315.4.0-28.325.4.0-30.34 Show 7 moreShow less 5.4.0-31.355.4.0-33.375.4.0-34.385.4.0-36.415.4.0-37.425.4.0-39.445.4.0-40.45	None known
`linux-riscv-5.8` Ubuntu:20.04:LTS	All versions, plus listed versions 5.8.0-14.16~20.04.15.8.0-14.16~20.04.35.8.0-16.18~20.04.15.8.0-17.19~20.04.15.8.0-18.20~20.04.1 Show 5 moreShow less 5.8.0-20.22~20.04.15.8.0-22.24~20.04.15.8.0-25.27~20.04.15.8.0-26.28~20.04.15.8.0-29.31~20.04.1	None known

History

History
Recorded	Changed	Sources
Nov 3, 2026	aliases, products	EUVD
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-4023 is a medium vulnerability (CVSS 5.5) in Linux Kernel, published March 9, 2022. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.24%, the 14th percentile. Fixed in linux 5.15.3-1.