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CVE-2021-43057

An issue was discovered in the Linux kernel before 5.14.8. A use-after-free in...

7.8 HighFix available

An issue was discovered in the Linux kernel before 5.14.8. A use-after-free in selinux_ptrace_traceme (aka the SELinux handler for PTRACE_TRACEME) could be used by local attackers to cause memory corruption and escalate privileges, aka CID-a3727a8bac0a. This occurs because of an attempt to access the subjective credentials of another task.

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
High
Integrity
High
Availability
High

Exploit likelihood

0.49%Up 0.1 points since Oct 28, 2021
90%50%10%1%

What each source reports

NVD Score used 7.8

An issue was discovered in the Linux kernel before 5.14.8. A use-after-free in selinux_ptrace_traceme (aka the SELinux handler for PTRACE_TRACEME) could be used by local attackers to cause memory corruption and escalate privileges, aka CID-a3727a8bac0a. This occurs because of an attempt to access the subjective credentials of another task.

Record
CVE-2021-43057
CVSS 3.1
7.8 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS 2.0
7.2 HighAV:L/AC:L/Au:N/C:C/I:C/A:C
Weakness
CWE-416
Updated
2026-11-02
CVE List No score

An issue was discovered in the Linux kernel before 5.14.8. A use-after-free in selinux_ptrace_traceme (aka the SELinux handler for PTRACE_TRACEME) could be used by local attackers to cause memory corruption and escalate privileges, aka CID-a3727a8bac0a. This occurs because of an attempt to access the subjective credentials of another task.

Record
CVE-2021-43057
Updated
2026-11-02
EUVDEUVD-2021-30010 No score

An issue was discovered in the Linux kernel before 5.14.8. A use-after-free in selinux_ptrace_traceme (aka the SELinux handler for PTRACE_TRACEME) could be used by local attackers to cause memory corruption and escalate privileges, aka CID-a3727a8bac0a. This occurs because of an attempt to access the subjective credentials of another task.

Record
EUVD-2021-30010
Updated
2026-11-03
GitHub AdvisoriesGHSA-h3xq-35q6-gh9g 7.8

An issue was discovered in the Linux kernel before 5.14.8. A use-after-free in...

An issue was discovered in the Linux kernel before 5.14.8. A use-after-free in selinux_ptrace_traceme (aka the SELinux handler for PTRACE_TRACEME) could be used by local attackers to cause memory corruption and escalate privileges, aka CID-a3727a8bac0a. This occurs because of an attempt to access the subjective credentials of another task.

Record
GHSA-h3xq-35q6-gh9g
CVSS 3.1
7.8 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-416
Updated
2026-11-02
OSVAZL-6602 7.8

CVE-2021-43057 affecting package kernel for versions less than 5.15.2.1-1

An issue was discovered in the Linux kernel before 5.14.8. A use-after-free in selinux_ptrace_traceme (aka the SELinux handler for PTRACE_TRACEME) could be used by local attackers to cause memory corruption and escalate privileges, aka CID-a3727a8bac0a. This occurs because of an attempt to access the subjective credentials of another task.

Record
AZL-6602
CVSS 3.1
7.8 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSV 7.8

An issue was discovered in the Linux kernel before 5.14.8. A use-after-free in selinux_ptrace_traceme (aka the SELinux handler for PTRACE_TRACEME) could be used by local attackers to cause memory corruption and escalate privileges, aka CID-a3727a8bac0a. This occurs because of an attempt to access the subjective credentials of another task.

Record
CVE-2021-43057
CVSS 3.1
7.8 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVDEBIAN-CVE-2021-43057 7.8

An issue was discovered in the Linux kernel before 5.14.8. A use-after-free in selinux_ptrace_traceme (aka the SELinux handler for PTRACE_TRACEME) could be used by local attackers to cause memory corruption and escalate privileges, aka CID-a3727a8bac0a. This occurs because of an attempt to access the subjective credentials of another task.

Record
DEBIAN-CVE-2021-43057
CVSS 3.1
7.8 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVUBUNTU-CVE-2021-43057 7.8

An issue was discovered in the Linux kernel before 5.14.8. A use-after-free in selinux_ptrace_traceme (aka the SELinux handler for PTRACE_TRACEME) could be used by local attackers to cause memory corruption and escalate privileges, aka CID-a3727a8bac0a. This occurs because of an attempt to access the subjective credentials of another task.

Record
UBUNTU-CVE-2021-43057
CVSS 3.1
7.8 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVUSN-5162-1 No score

linux, linux-aws, linux-azure, linux-gcp, linux-kvm, linux-oem-5.13, linux-oracle, linux-raspi vulnerabilities

Ilja Van Sprundel discovered that the SCTP implementation in the Linux kernel did not properly perform size validations on incoming packets in some situations. An attacker could possibly use this to expose sensitive information (kernel memory). (CVE-2021-3655)

It was discovered that the AMD Cryptographic Coprocessor (CCP) driver in the Linux kernel did not properly deallocate memory in some error conditions. A local attacker could use this to cause a denial of service (memory exhaustion). (CVE-2021-3744, CVE-2021-3764)

It was discovered that the Aspeed Low Pin Count (LPC) Bus Controller implementation in the Linux kernel did not properly perform boundary checks in some situations, allowing out-of-bounds write access. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. In Ubuntu, this issue only affected systems running armhf kernels. (CVE-2021-42252)

Jann Horn discovered that the SELinux subsystem in the Linux kernel did not properly handle subjective credentials for tasks in some situations. On systems where SELinux has been enabled, a local attacker could possibly use this to cause a denial of service (system crash) or execute arbitrary code. (CVE-2021-43057)

Record
USN-5162-1
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
kernel
Azure Linux:2
before 5.15.2.1-1
5.15.2.1-1
linux
Debian:12
before 5.14.9-1
5.14.9-1
linux
Debian:13
before 5.14.9-1
5.14.9-1
linux
Debian:14
before 5.14.9-1
5.14.9-1
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
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
Show 21 moreShow less
Affected packages
PackageAffectedFixed
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-hwe-5.13
Ubuntu:20.04:LTS
before 5.13.0-22.22~20.04.1, plus listed versions
5.13.0-21.21~20.04.1
5.13.0-22.22~20.04.1
linux-oem-5.13
Ubuntu:20.04:LTS
before 5.13.0-1020.24, plus listed versions
5.13.0-1009.105.13.0-1010.115.13.0-1012.165.13.0-1014.185.13.0-1017.215.13.0-1019.23
5.13.0-1020.24
linux-oem-5.14
Ubuntu:20.04:LTS
before 5.14.0-1005.5, plus listed versions
5.14.0-1004.4
5.14.0-1005.5
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-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
linux-oem-5.13
Ubuntu:20.04:LTS
From an advisory covering 5 CVEs
before 5.13.0-1020.24, plus listed versions
5.13.0-1009.105.13.0-1010.115.13.0-1012.165.13.0-1014.185.13.0-1017.215.13.0-1019.23
5.13.0-1020.24

History

History
RecordedChangedSources
affected, facts
aliasesEUVD
first indexedCVE List, GitHub Advisories, NVD, OSV

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

In short

CVE-2021-43057 is a high vulnerability (CVSS 7.8) in Linux Kernel, published October 28, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.49%, the 42nd percentile. Fixed in kernel 5.15.2.1-1.

References

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