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High · 7.8 CVE-2021-47461 EUVD-2021-34466GHSA-q3gr-2743-cwm5

userfaultfd: fix a race between writeprotect and exit_mmap()

Published May 22, 2024 · Updated Aug 5, 2026 · Assigned by Linux

Vendor: Linux Product: Linux Package: linux Package: linux-allwinner-5.19 Package: linux-aws-5.0 Package: linux-aws-5.11 Package: linux-aws-5.13 Package: linux-aws-5.19 Package: linux-aws-5.3 Package: linux-aws-5.8 Package: linux-aws-6.2 Package: linux-azure Package: linux-azure-5.11 Package: linux-azure-5.13 Package: linux-azure-5.19 Package: linux-azure-5.3 Package: linux-azure-5.8 Package: linux-azure-6.2 Package: linux-azure-edge Package: linux-azure-fde Package: linux-azure-fde-5.19 Package: linux-azure-fde-6.2 Package: linux-gcp Package: linux-gcp-5.11 Package: linux-gcp-5.13 Package: linux-gcp-5.19 Package: linux-gcp-5.3 Package: linux-gcp-5.8 Package: linux-gcp-6.2 Package: linux-gke Package: linux-gke-4.15 Package: linux-gke-5.15 Package: linux-gke-5.4 Package: linux-gkeop-5.4 Package: linux-hwe Package: linux-hwe-5.11 Package: linux-hwe-5.13 Package: linux-hwe-5.19 Package: linux-hwe-5.8 Package: linux-hwe-6.2 Package: linux-hwe-edge Package: linux-intel-5.13 Package: linux-lowlatency-hwe-5.19 Package: linux-lowlatency-hwe-6.2 Package: linux-nvidia-6.2 Package: linux-oem Package: linux-oem-5.10 Package: linux-oem-5.13 Package: linux-oem-5.14 Package: linux-oem-5.17 Package: linux-oem-5.6 Package: linux-oem-6.0 Package: linux-oem-6.1 Package: linux-oracle-5.0 Package: linux-oracle-5.11 Package: linux-oracle-5.13 Package: linux-oracle-5.3 Package: linux-oracle-5.8 Package: linux-raspi2 Package: linux-riscv Package: linux-riscv-5.11 Package: linux-riscv-5.19 Package: linux-riscv-5.8 Package: linux-starfive-5.19 Package: linux-starfive-6.2 Platform: Linux Ecosystem: Debian Ecosystem: Ubuntu

Description

In the Linux kernel, the following vulnerability has been resolved:

userfaultfd: fix a race between writeprotect and exit_mmap()

A race is possible when a process exits, its VMAs are removed by
exit_mmap() and at the same time userfaultfd_writeprotect() is called.

The race was detected by KASAN on a development kernel, but it appears
to be possible on vanilla kernels as well.

Use mmget_not_zero() to prevent the race as done in other userfaultfd
operations.

Affected products

VendorProductAffectedFixed
Linux Linux 5.7 5.10.76

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Debian 14 linux 5.14.16-1 —
Debian 13 linux 5.14.16-1 —
Debian 12 linux 5.14.16-1 —
ReleasePackageFixed inAdvisory
Ubuntu 22.04 LTS linux-riscv +20 No fix yet —
Ubuntu 20.04 LTS linux-gke +26 No fix yet —
Ubuntu 18.04 LTS linux-gcp +14 No fix yet —
Ubuntu 16.04 LTS linux-hwe-edge No fix yet —
ReleasePackageFixed inAdvisory
RHEL 8 kernel-rt +12 4.18.0-553.16.1.rt7.357.el8_10 RHSA-2024:5102
RHEL 8 perf +26 4.18.0-553.16.1.el8_10 RHSA-2024:5101
Show 4 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
RHEL 8.8 EUS perf +26 4.18.0-477.81.1.el8_8 RHSA-2024:10262
RHEL 8.6 TUS perf +16 4.18.0-372.121.1.el8_6 RHSA-2024:6297
RHEL 8.6 E4S perf +24 4.18.0-372.121.1.el8_6 RHSA-2024:6297
RHEL 8.6 AUS perf +16 4.18.0-372.121.1.el8_6 RHSA-2024:6297

AlmaLinux

Errata ↗
ReleasePackageFixed inAdvisory
AlmaLinux 8 kernel-rt +11 4.18.0-553.16.1.rt7.357.el8_10 ALSA-2024:5102
AlmaLinux 8 perf +24 4.18.0-553.16.1.el8_10 ALSA-2024:5101

Rocky Linux

Errata ↗
ReleasePackageFixed inAdvisory
Rocky Linux 8 kernel 4.18.0-553.16.1.el8_10 RXSA-2024:5101, RLSA-2024:5101
Rocky Linux 8 kernel-rt 4.18.0-553.16.1.rt7.357.el8_10 RLSA-2024:5102
ReleasePackageFixed inAdvisory
SLES 15 SP5 kernel-64kb +6 5.14.21-150500.55.68.1 SUSE-SU-2024:2190-1
SLES 15 SP5 kernel-azure +2 5.14.21-150500.33.57.1 SUSE-SU-2024:2019-1
SLES 15 SP5 kernel-default-base 5.14.21-150500.55.68.1.150500.6.31.1 SUSE-SU-2024:2190-1
SLES 15 SP4 kernel-64kb +4 5.14.21-150400.24.122.2 SUSE-SU-2024:2189-1
SLES 15 SP4 kernel-default-base 5.14.21-150400.24.122.2.150400.24.58.2 SUSE-SU-2024:2189-1
SLES 15 SP4 kernel-syms +1 5.14.21-150400.24.122.1 SUSE-SU-2024:2189-1
Show 10 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
SLES for SAP 15 SP4 kernel-default-base 5.14.21-150400.24.122.2.150400.24.58.2 SUSE-SU-2024:2189-1
SLES for SAP 15 SP4 kernel-docs +2 5.14.21-150400.24.122.2 SUSE-SU-2024:2189-1
SLES for SAP 15 SP4 kernel-syms +1 5.14.21-150400.24.122.1 SUSE-SU-2024:2189-1
SLE Micro 5.5 kernel-default 5.14.21-150500.55.68.1 SUSE-SU-2024:2190-1
SLE Micro 5.5 kernel-default-base 5.14.21-150500.55.68.1.150500.6.31.1 SUSE-SU-2024:2190-1
SLE Micro 5.5 kernel-rt +1 5.14.21-150500.13.58.1 SUSE-SU-2024:2008-1
SLE Micro 5.4 kernel-default 5.14.21-150400.24.122.2 SUSE-SU-2024:2189-1
SLE Micro 5.4 kernel-default-base 5.14.21-150400.24.122.2.150400.24.58.2 SUSE-SU-2024:2189-1
SLE Micro 5.4 kernel-rt +1 5.14.21-150400.15.82.1 SUSE-SU-2024:2011-1
SLE Micro 5.3 kernel-default 5.14.21-150400.24.122.2 SUSE-SU-2024:2189-1
SLE Micro 5.3 kernel-default-base 5.14.21-150400.24.122.2.150400.24.58.2 SUSE-SU-2024:2189-1
SLE Micro 5.3 kernel-rt +1 5.14.21-150400.15.82.1 SUSE-SU-2024:2011-1
SLE Live Patching 15 SP5 kernel-default 5.14.21-150500.55.68.1 SUSE-SU-2024:2190-1
SLE Live Patching 15 SP5 kernel-livepatch-SLE15-SP5_Update_15 +1 1-150500.11.3.1 SUSE-SU-2024:2190-1, SUSE-SU-2024:2008-1
SLE Live Patching 15 SP4 kernel-default 5.14.21-150400.24.122.2 SUSE-SU-2024:2189-1
SLE Live Patching 15 SP4 kernel-livepatch-SLE15-SP4_Update_27 1-150400.9.3.2 SUSE-SU-2024:2189-1
SLE HPC 15 SP4 kernel-64kb +3 5.14.21-150400.24.122.2 SUSE-SU-2024:2189-1
SLE HPC 15 SP4 kernel-default-base 5.14.21-150400.24.122.2.150400.24.58.2 SUSE-SU-2024:2189-1
SLE HPC 15 SP4 kernel-syms +1 5.14.21-150400.24.122.1 SUSE-SU-2024:2189-1
SUSE Real Time Module 15 SP5 kernel-rt +3 5.14.21-150500.13.58.1 SUSE-SU-2024:2008-1
SUSE Manager Server 4.3 kernel-default +1 5.14.21-150400.24.122.2 SUSE-SU-2024:2189-1
SUSE Manager Server 4.3 kernel-default-base 5.14.21-150400.24.122.2.150400.24.58.2 SUSE-SU-2024:2189-1
SUSE Manager Server 4.3 kernel-syms +1 5.14.21-150400.24.122.1 SUSE-SU-2024:2189-1
SUSE Manager Proxy 4.3 kernel-default 5.14.21-150400.24.122.2 SUSE-SU-2024:2189-1
SUSE Manager Proxy 4.3 kernel-default-base 5.14.21-150400.24.122.2.150400.24.58.2 SUSE-SU-2024:2189-1
SUSE Manager Proxy 4.3 kernel-syms +1 5.14.21-150400.24.122.1 SUSE-SU-2024:2189-1
ReleasePackageFixed inAdvisory
openSUSE Leap 15.5 dtb-aarch64 +10 5.14.21-150500.55.68.1 SUSE-SU-2024:2190-1
openSUSE Leap 15.5 kernel-azure +2 5.14.21-150500.33.57.1 SUSE-SU-2024:2019-1
openSUSE Leap 15.5 kernel-default-base 5.14.21-150500.55.68.1.150500.6.31.1 SUSE-SU-2024:2190-1
openSUSE Leap 15.5 kernel-rt +3 5.14.21-150500.13.58.1 SUSE-SU-2024:2008-1
Show 2 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
openSUSE Leap Micro 5.4 kernel-default 5.14.21-150400.24.122.2 SUSE-SU-2024:2189-1
openSUSE Leap Micro 5.4 kernel-default-base 5.14.21-150400.24.122.2.150400.24.58.2 SUSE-SU-2024:2189-1
openSUSE Leap Micro 5.4 kernel-rt 5.14.21-150400.15.82.1 SUSE-SU-2024:2011-1
openSUSE Leap Micro 5.3 kernel-default 5.14.21-150400.24.122.2 SUSE-SU-2024:2189-1
openSUSE Leap Micro 5.3 kernel-default-base 5.14.21-150400.24.122.2.150400.24.58.2 SUSE-SU-2024:2189-1
openSUSE Leap Micro 5.3 kernel-rt 5.14.21-150400.15.82.1 SUSE-SU-2024:2011-1

Oracle Linux

ReleasePackageFixed inAdvisory
Oracle Linux 8 perf +19 4.18.0-553.16.1.el8_10 ELSA-2024-5101

Advisories 17

References