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Fencer Vulns
high 7.0

CVE-2021-4083 json

A read-after-free memory flaw was found in the Linux kernel's garbage collection for Unix domain socket file handlers in the way users call…

published 2022-01-18 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-33972

cvss
7.0
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 24%
public exploits
0
none known

Summary

A read-after-free memory flaw was found in the Linux kernel's garbage collection for Unix domain socket file handlers in the way users call close() and fget() simultaneously and can potentially trigger a race condition. This flaw allows a local user to crash the system or escalate their privileges on the system. This flaw affects Linux kernel versions prior to 5.16-rc4.

Patch / fix

  • linux linux_kernel 4.4.294, 4.9.292, 4.14.257, 4.19.220, 5.4.164, 5.10.84, 5.15.7
  • linux Debian 14, Debian 13, Debian 12 5.15.5-2

debian advisories DEBIAN-CVE-2021-4083

  • linux Ubuntu 18.04 LTS 4.15.0-169.177
  • linux Ubuntu 20.04 LTS 5.4.0-100.113
  • linux-aws Ubuntu 18.04 LTS 4.15.0-1121.129
  • linux-aws Ubuntu 20.04 LTS 5.4.0-1066.69
  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1065.69
  • linux-gke Ubuntu 20.04 LTS 5.4.0-1063.66
  • linux-ibm Ubuntu 20.04 LTS 5.4.0-1015.16
  • linux-kvm Ubuntu 18.04 LTS 4.15.0-1107.109

ubuntu advisories UBUNTU-CVE-2021-4083

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • redhat-virtualization-host rhev hypervisor 4.4 4.5.0-202205291010_8.6
  • redhat-virtualization-host-image-update rhev hypervisor 4.4 4.5.0-202205291010_8.6
  • redhat-virtualization-host RHEL 7 4.3.22-20220330.1.el7_9
  • redhat-virtualization-host-image-update RHEL 7 4.3.22-20220330.1.el7_9
  • kernel RHEL 8 4.18.0-372.9.1.el8
  • perf RHEL 8 4.18.0-372.9.1.el8
  • bpftool RHEL 8 4.18.0-372.9.1.el8
  • kernel-core RHEL 8 4.18.0-372.9.1.el8

red hat advisories RHSA-2022:4896RHSA-2022:1263RHSA-2022:1988RHSA-2022:1418RHSA-2022:1413RHSA-2022:1373

  • kernel-rt SLE Real Time 12 SP5 4.12.14-10.78.1
  • kernel-syms-rt SLE Real Time 12 SP5 4.12.14-10.78.1
  • kernel-rt_debug SLE Real Time 12 SP5 4.12.14-10.78.1
  • kernel-source-rt SLE Real Time 12 SP5 4.12.14-10.78.1
  • kernel-syms SLES 12 SP2-BCL 4.4.121-92.164.1
  • kernel-source SLES 12 SP2-BCL 4.4.121-92.164.1
  • kernel-default SLES 12 SP2-BCL 4.4.121-92.164.1
  • kernel-azure SLES for SAP 12 SP5, SLES 12 SP5 4.12.14-16.88.1

suse advisories SUSE-SU-2022:0555-1SUSE-SU-2022:0552-1SUSE-SU-2022:0477-1SUSE-SU-2022:0463-1SUSE-SU-2022:0436-1SUSE-SU-2022:0418-1

  • kernel-default openSUSE Leap 15.3 4.12.14-197.105.1
  • kernel-vanilla openSUSE Leap 15.3 4.12.14-197.105.1
  • kernel-kvmsmall openSUSE Leap 15.3 4.12.14-197.105.1
  • kernel-zfcpdump openSUSE Leap 15.3 4.12.14-197.105.1
  • dtb-aarch64 openSUSE Leap 15.3 5.3.18-150300.59.43.1
  • kernel-64kb openSUSE Leap 15.3 5.3.18-150300.59.43.1
  • kernel-syms openSUSE Leap 15.3 5.3.18-150300.59.43.1
  • kernel-obs-qa openSUSE Leap 15.3 5.3.18-150300.59.43.1

opensuse advisories openSUSE-SU-2022:0366-1openSUSE-SU-2022:0198-1openSUSE-SU-2022:0169-1

  • kernel AlmaLinux 8 4.18.0-372.9.1.el8
  • perf AlmaLinux 8 4.18.0-372.9.1.el8
  • bpftool AlmaLinux 8 4.18.0-372.9.1.el8
  • kernel-core AlmaLinux 8 4.18.0-372.9.1.el8
  • kernel-tools AlmaLinux 8 4.18.0-372.9.1.el8
  • python3-perf AlmaLinux 8 4.18.0-372.9.1.el8
  • kernel-modules AlmaLinux 8 4.18.0-372.9.1.el8
  • kernel-debug-core AlmaLinux 8 4.18.0-372.9.1.el8

almalinux advisories ALSA-2022:1988

  • kernel Rocky Linux 8 4.18.0-372.9.1.el8
  • kernel-rt Rocky Linux 8 4.18.0-372.9.1.rt7.166.el8

rocky linux advisories RLSA-2022:1988RLSA-2022:1975

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-4083 updated cvss 7.4

kernel: fget: check that the fd still exists after getting a ref to it

  • Red Hat CodeReady Linux Builder EUS (v. 8.2) kernel-debuginfo-common-x86_64 4.18.0-193.79.1.el8_2, kernel-debuginfo-common-aarch64 4.18.0-193.79.1.el8_2, kernel-debuginfo-common-ppc64le 4.18.0-193.79.1.el8_2
    fixed: vendor fix RHSA-2022:0820
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-372.9.1.el8, kernel 4.18.0-372.9.1.el8, bpftool 4.18.0-372.9.1.el8, kernel-core 4.18.0-372.9.1.el8, kernel-tools 4.18.0-372.9.1.el8, python3-perf 4.18.0-372.9.1.el8, +15 more
    fixed: vendor fix RHSA-2022:1988
  • Red Hat Enterprise Linux BaseOS E4S (v. 8.1) perf 4.18.0-147.64.1.el8_1, kernel 4.18.0-147.64.1.el8_1, bpftool 4.18.0-147.64.1.el8_1, kernel-core 4.18.0-147.64.1.el8_1, kernel-tools 4.18.0-147.64.1.el8_1, python3-perf 4.18.0-147.64.1.el8_1, +19 more
    fixed: vendor fix RHSA-2022:0823
  • Red Hat Enterprise Linux BaseOS EUS (v. 8.2) perf 4.18.0-193.79.1.el8_2, kernel 4.18.0-193.79.1.el8_2, bpftool 4.18.0-193.79.1.el8_2, kernel-core 4.18.0-193.79.1.el8_2, kernel-tools 4.18.0-193.79.1.el8_2, python3-perf 4.18.0-193.79.1.el8_2, +25 more
    fixed: vendor fix RHSA-2022:0820
  • Red Hat Enterprise Linux BaseOS EUS (v.8.4) perf 4.18.0-305.45.1.el8_4, kernel 4.18.0-305.45.1.el8_4, bpftool 4.18.0-305.45.1.el8_4, kpatch-patch-4_18_0-305 1-12.el8, kernel-core 4.18.0-305.45.1.el8_4, kernel-tools 4.18.0-305.45.1.el8_4, +28 more
    fixed: vendor fix RHSA-2022:1455
  • Red Hat Enterprise Linux Client (v. 7) perf 3.10.0-1160.62.1.el7, kernel 3.10.0-1160.62.1.el7, bpftool 3.10.0-1160.62.1.el7, python-perf 3.10.0-1160.62.1.el7, kernel-tools 3.10.0-1160.62.1.el7, kernel-tools-libs 3.10.0-1160.62.1.el7, +2 more Red Hat Enterprise Linux Client Optional (v. 7) kernel-debuginfo-common-x86_64 3.10.0-1160.62.1.el7 Red Hat Enterprise Linux ComputeNode Optional (v. 7) kernel-debuginfo-common-x86_64 3.10.0-1160.62.1.el7
    fixed: vendor fix RHSA-2022:1198
  • Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-372.9.1.el8, kernel-debuginfo-common-aarch64 4.18.0-372.9.1.el8, kernel-debuginfo-common-ppc64le 4.18.0-372.9.1.el8
    fixed: vendor fix RHSA-2022:1988
  • Red Hat Enterprise Linux CRB EUS (v.8.4) kernel-debuginfo-common-x86_64 4.18.0-305.45.1.el8_4, kernel-debuginfo-common-aarch64 4.18.0-305.45.1.el8_4, kernel-debuginfo-common-ppc64le 4.18.0-305.45.1.el8_4
    fixed: vendor fix RHSA-2022:1455
show 27 more
  • Red Hat Enterprise Linux for Real Time (v. 7) kernel-rt 3.10.0-1160.62.1.rt56.1203.el7, kernel-rt-trace 3.10.0-1160.62.1.rt56.1203.el7, kernel-rt-debuginfo-common-x86_64 3.10.0-1160.62.1.rt56.1203.el7 Red Hat Enterprise Linux for Real Time for NFV (v. 7) kernel-rt 3.10.0-1160.62.1.rt56.1203.el7, kernel-rt-kvm 3.10.0-1160.62.1.rt56.1203.el7, kernel-rt-trace 3.10.0-1160.62.1.rt56.1203.el7, kernel-rt-debug-kvm 3.10.0-1160.62.1.rt56.1203.el7, kernel-rt-trace-kvm 3.10.0-1160.62.1.rt56.1203.el7, kernel-rt-debuginfo-common-x86_64 3.10.0-1160.62.1.rt56.1203.el7
    fixed: vendor fix RHSA-2022:1199
  • Red Hat Enterprise Linux NFV (v. 8) kernel-rt 4.18.0-372.9.1.rt7.166.el8, kernel-rt-kvm 4.18.0-372.9.1.rt7.166.el8, kernel-rt-core 4.18.0-372.9.1.rt7.166.el8, kernel-rt-modules 4.18.0-372.9.1.rt7.166.el8, kernel-rt-debug-kvm 4.18.0-372.9.1.rt7.166.el8, kernel-rt-debug-core 4.18.0-372.9.1.rt7.166.el8, +4 more
    fixed: vendor fix RHSA-2022:1975
  • Red Hat Enterprise Linux NFV EUS (v.8.4) kernel-rt 4.18.0-305.45.1.rt7.117.el8_4, kernel-rt-kvm 4.18.0-305.45.1.rt7.117.el8_4, kernel-rt-core 4.18.0-305.45.1.rt7.117.el8_4, kernel-rt-modules 4.18.0-305.45.1.rt7.117.el8_4, kernel-rt-debug-kvm 4.18.0-305.45.1.rt7.117.el8_4, kernel-rt-debug-core 4.18.0-305.45.1.rt7.117.el8_4, +4 more
    fixed: vendor fix RHSA-2022:1413
  • Red Hat Enterprise Linux Real Time EUS (v. 8.2) kernel-rt 4.18.0-193.79.1.rt13.129.el8_2, kernel-rt-core 4.18.0-193.79.1.rt13.129.el8_2, kernel-rt-modules 4.18.0-193.79.1.rt13.129.el8_2, kernel-rt-debug-core 4.18.0-193.79.1.rt13.129.el8_2, kernel-rt-debug-modules 4.18.0-193.79.1.rt13.129.el8_2, kernel-rt-modules-extra 4.18.0-193.79.1.rt13.129.el8_2, +2 more Red Hat Enterprise Linux Real Time for NFV EUS (v. 8.2) kernel-rt 4.18.0-193.79.1.rt13.129.el8_2, kernel-rt-kvm 4.18.0-193.79.1.rt13.129.el8_2, kernel-rt-core 4.18.0-193.79.1.rt13.129.el8_2, kernel-rt-modules 4.18.0-193.79.1.rt13.129.el8_2, kernel-rt-debug-kvm 4.18.0-193.79.1.rt13.129.el8_2, kernel-rt-debug-core 4.18.0-193.79.1.rt13.129.el8_2, +4 more
    fixed: vendor fix RHSA-2022:0821
  • Red Hat Enterprise Linux RT (v. 8) kernel-rt 4.18.0-372.9.1.rt7.166.el8, kernel-rt-core 4.18.0-372.9.1.rt7.166.el8, kernel-rt-modules 4.18.0-372.9.1.rt7.166.el8, kernel-rt-debug-core 4.18.0-372.9.1.rt7.166.el8, kernel-rt-debug-modules 4.18.0-372.9.1.rt7.166.el8, kernel-rt-modules-extra 4.18.0-372.9.1.rt7.166.el8, +2 more
    fixed: vendor fix RHSA-2022:1975
  • Red Hat Enterprise Linux RT EUS (v.8.4) kernel-rt 4.18.0-305.45.1.rt7.117.el8_4, kernel-rt-core 4.18.0-305.45.1.rt7.117.el8_4, kernel-rt-modules 4.18.0-305.45.1.rt7.117.el8_4, kernel-rt-debug-core 4.18.0-305.45.1.rt7.117.el8_4, kernel-rt-debug-modules 4.18.0-305.45.1.rt7.117.el8_4, kernel-rt-modules-extra 4.18.0-305.45.1.rt7.117.el8_4, +2 more
    fixed: vendor fix RHSA-2022:1413
  • Red Hat Enterprise Linux Server (v. 7) perf 3.10.0-1160.62.1.el7, kernel 3.10.0-1160.62.1.el7, bpftool 3.10.0-1160.62.1.el7, python-perf 3.10.0-1160.62.1.el7, kernel-kdump 3.10.0-1160.62.1.el7, kernel-tools 3.10.0-1160.62.1.el7, +17 more
    fixed: vendor fix RHSA-2022:1198
  • Red Hat Enterprise Linux Server AUS (v. 7.3) perf 3.10.0-514.101.1.el7, kernel 3.10.0-514.101.1.el7, python-perf 3.10.0-514.101.1.el7, kernel-tools 3.10.0-514.101.1.el7, kernel-tools-libs 3.10.0-514.101.1.el7, kernel-abi-whitelists 3.10.0-514.101.1.el7, +1 more
    fixed: vendor fix RHSA-2022:2189
  • Red Hat Enterprise Linux Server AUS (v. 7.4) perf 3.10.0-693.99.1.el7, kernel 3.10.0-693.99.1.el7, python-perf 3.10.0-693.99.1.el7, kernel-tools 3.10.0-693.99.1.el7, kernel-tools-libs 3.10.0-693.99.1.el7, kernel-abi-whitelists 3.10.0-693.99.1.el7, +1 more
    fixed: vendor fix RHSA-2022:1104
  • Red Hat Enterprise Linux Server AUS (v. 7.6) perf 3.10.0-957.92.1.el7, kernel 3.10.0-957.92.1.el7, bpftool 3.10.0-957.92.1.el7, python-perf 3.10.0-957.92.1.el7, kernel-tools 3.10.0-957.92.1.el7, kernel-tools-libs 3.10.0-957.92.1.el7, +2 more
    fixed: vendor fix RHSA-2022:1107
  • Red Hat Enterprise Linux Server AUS (v. 7.7) perf 3.10.0-1062.66.1.el7, kernel 3.10.0-1062.66.1.el7, bpftool 3.10.0-1062.66.1.el7, python-perf 3.10.0-1062.66.1.el7, kernel-tools 3.10.0-1062.66.1.el7, kernel-tools-libs 3.10.0-1062.66.1.el7, +2 more
    fixed: vendor fix RHSA-2022:1324
  • Red Hat Enterprise Linux Server E4S (v. 7.6) perf 3.10.0-957.92.1.el7, kernel 3.10.0-957.92.1.el7, python-perf 3.10.0-957.92.1.el7, kernel-tools 3.10.0-957.92.1.el7, kpatch-patch-3_10_0-957_72_1 1-6.el7, kpatch-patch-3_10_0-957_76_1 1-6.el7, +10 more
    fixed: vendor fix RHSA-2022:1107
  • Red Hat Enterprise Linux Server E4S (v. 7.7) perf 3.10.0-1062.66.1.el7, kernel 3.10.0-1062.66.1.el7, bpftool 3.10.0-1062.66.1.el7, python-perf 3.10.0-1062.66.1.el7, kernel-tools 3.10.0-1062.66.1.el7, kpatch-patch-3_10_0-1062_49_1 1-6.el7, +12 more
    fixed: vendor fix RHSA-2022:1324
  • Red Hat Enterprise Linux Server Optional (v. 7) kernel-debuginfo-common-ppc64 3.10.0-1160.62.1.el7, kernel-debuginfo-common-x86_64 3.10.0-1160.62.1.el7, kernel-debuginfo-common-ppc64le 3.10.0-1160.62.1.el7
    fixed: vendor fix RHSA-2022:1198
  • Red Hat Enterprise Linux Server Optional AUS (v. 7.3) kernel-debuginfo-common-x86_64 3.10.0-514.101.1.el7
    fixed: vendor fix RHSA-2022:2189
  • Red Hat Enterprise Linux Server Optional AUS (v. 7.4) kernel-debuginfo-common-x86_64 3.10.0-693.99.1.el7
    fixed: vendor fix RHSA-2022:1104
  • Red Hat Enterprise Linux Server Optional AUS (v. 7.6) kernel-debuginfo-common-x86_64 3.10.0-957.92.1.el7
    fixed: vendor fix RHSA-2022:1107
  • Red Hat Enterprise Linux Server Optional AUS (v. 7.7) kernel-debuginfo-common-x86_64 3.10.0-1062.66.1.el7
    fixed: vendor fix RHSA-2022:1324
  • Red Hat Enterprise Linux Server Optional E4S (v. 7.6) kernel-debuginfo-common-x86_64 3.10.0-957.92.1.el7, kernel-debuginfo-common-ppc64le 3.10.0-957.92.1.el7
    fixed: vendor fix RHSA-2022:1107
  • Red Hat Enterprise Linux Server Optional E4S (v. 7.7) kernel-debuginfo-common-x86_64 3.10.0-1062.66.1.el7, kernel-debuginfo-common-ppc64le 3.10.0-1062.66.1.el7
    fixed: vendor fix RHSA-2022:1324
  • Red Hat Enterprise Linux Server Optional TUS (v. 7.6) kernel-debuginfo-common-x86_64 3.10.0-957.92.1.el7
    fixed: vendor fix RHSA-2022:1107
  • Red Hat Enterprise Linux Server Optional TUS (v. 7.7) kernel-debuginfo-common-x86_64 3.10.0-1062.66.1.el7
    fixed: vendor fix RHSA-2022:1324
  • Red Hat Enterprise Linux Server TUS (v. 7.6) perf 3.10.0-957.92.1.el7, kernel 3.10.0-957.92.1.el7, bpftool 3.10.0-957.92.1.el7, python-perf 3.10.0-957.92.1.el7, kernel-tools 3.10.0-957.92.1.el7, kernel-tools-libs 3.10.0-957.92.1.el7, +2 more
    fixed: vendor fix RHSA-2022:1107
  • Red Hat Enterprise Linux Server TUS (v. 7.7) perf 3.10.0-1062.66.1.el7, kernel 3.10.0-1062.66.1.el7, bpftool 3.10.0-1062.66.1.el7, python-perf 3.10.0-1062.66.1.el7, kernel-tools 3.10.0-1062.66.1.el7, kernel-tools-libs 3.10.0-1062.66.1.el7, +2 more
    fixed: vendor fix RHSA-2022:1324
  • Red Hat Enterprise Linux Workstation (v. 7) perf 3.10.0-1160.62.1.el7, kernel 3.10.0-1160.62.1.el7, bpftool 3.10.0-1160.62.1.el7, python-perf 3.10.0-1160.62.1.el7, kernel-tools 3.10.0-1160.62.1.el7, kernel-tools-libs 3.10.0-1160.62.1.el7, +2 more Red Hat Enterprise Linux Workstation Optional (v. 7) kernel-debuginfo-common-x86_64 3.10.0-1160.62.1.el7
    fixed: vendor fix RHSA-2022:1198
  • Red Hat Virtualization 4 Hypervisor for RHEL 7 redhat-virtualization-host 4.3.22-20220330.1.el7_9, redhat-virtualization-host-image-update 4.3.22-20220330.1.el7_9
    fixed: vendor fix RHSA-2022:1263
  • Red Hat Virtualization 4 Hypervisor for RHEL 8 redhat-virtualization-host 4.5.0-202205291010_8.6, redhat-virtualization-host-image-update 4.5.0-202205291010_8.6
    fixed: vendor fix RHSA-2022:4896

1 more fixed, 5 more not affected in the full advisory

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.31% chance of exploitation in the next 30 days, higher than 24% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 7.0 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 6.9 AV:L/AC:M/Au:N/C:C/I:C/A:C

Affected products

  • n/a kernel

Classification

Weakness
  • CWE-416 Use After Free
  • CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.