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High · 7.8 CVE-2021-47248 EUVD-2021-33896GHSA-rr3f-v8j5-mmr6

udp: fix race between close() and udp_abort()

Published May 21, 2024 · Updated Aug 5, 2026 · Assigned by Linux

Vendor: Linux Product: Linux Package: linux Package: linux Package: linux-allwinner-5.19 Package: linux-aws 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-5.4 Package: linux-aws-5.8 Package: linux-aws-6.2 Package: linux-aws-fips Package: linux-aws-hwe Package: linux-azure Package: linux-azure-4.15 Package: linux-azure-5.11 Package: linux-azure-5.13 Package: linux-azure-5.19 Package: linux-azure-5.3 Package: linux-azure-5.4 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-azure-fips Package: linux-bluefield Package: linux-fips Package: linux-gcp Package: linux-gcp-4.15 Package: linux-gcp-5.11 Package: linux-gcp-5.13 Package: linux-gcp-5.19 Package: linux-gcp-5.3 Package: linux-gcp-5.4 Package: linux-gcp-5.8 Package: linux-gcp-6.2 Package: linux-gcp-fips Package: linux-gke Package: linux-gke-4.15 Package: linux-gke-5.15 Package: linux-gke-5.4 Package: linux-gkeop 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-5.4 Package: linux-hwe-5.8 Package: linux-hwe-6.2 Package: linux-hwe-edge Package: linux-intel-5.13 Package: linux-intel-iot-realtime Package: linux-kvm 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 Package: linux-oracle-5.0 Package: linux-oracle-5.11 Package: linux-oracle-5.13 Package: linux-oracle-5.3 Package: linux-oracle-5.4 Package: linux-oracle-5.8 Package: linux-raspi Package: linux-raspi-5.4 Package: linux-raspi-realtime Package: linux-raspi2 Package: linux-realtime 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 Package: linux-vmware Platform: Linux Ecosystem: Debian Ecosystem: Ubuntu

Description

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

udp: fix race between close() and udp_abort()

Kaustubh reported and diagnosed a panic in udp_lib_lookup().
The root cause is udp_abort() racing with close(). Both
racing functions acquire the socket lock, but udp{v6}_destroy_sock()
release it before performing destructive actions.

We can't easily extend the socket lock scope to avoid the race,
instead use the SOCK_DEAD flag to prevent udp_abort from doing
any action when the critical race happens.

Diagnosed-and-tested-by: Kaustubh Pandey <kapandey@codeaurora.org>

Affected products

VendorProductAffectedFixed
Linux Linux 4.9 4.9.274

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.

Debian

Security tracker ↗
ReleasePackageFixed inAdvisory
Debian 14 linux 5.10.46-1 —
Debian 13 linux 5.10.46-1 —
Debian 12 linux 5.10.46-1 —

Ubuntu

Security tracker ↗
ReleasePackageFixed inAdvisory
Ubuntu 24.04 LTS linux-raspi-realtime No fix yet —
Ubuntu 22.04 LTS linux-riscv +22 No fix yet —
Ubuntu 20.04 LTS linux 5.4.0-81.91 —
Ubuntu 20.04 LTS linux-aws 5.4.0-1055.58 —
Ubuntu 20.04 LTS linux-azure 5.4.0-1056.58 —
Ubuntu 20.04 LTS linux-bluefield 5.4.0-1019.22 —
Ubuntu 20.04 LTS linux-gcp 5.4.0-1051.55 —
Ubuntu 20.04 LTS linux-gke +26 No fix yet —
Ubuntu 20.04 LTS linux-gkeop 5.4.0-1022.23 —
Ubuntu 20.04 LTS linux-kvm 5.4.0-1045.47 —
Ubuntu 20.04 LTS linux-oracle 5.4.0-1053.57 —
Ubuntu 20.04 LTS linux-raspi 5.4.0-1042.46 —
Ubuntu 18.04 LTS linux 4.15.0-156.163 —
Ubuntu 18.04 LTS linux-aws 4.15.0-1111.118 —
Ubuntu 18.04 LTS linux-aws-5.4 5.4.0-1055.58~18.04.1 —
Ubuntu 18.04 LTS linux-azure-4.15 4.15.0-1123.136 —
Ubuntu 18.04 LTS linux-azure-5.4 5.4.0-1056.58~18.04.1 —
Ubuntu 18.04 LTS linux-gcp +14 No fix yet —
Ubuntu 18.04 LTS linux-gcp-4.15 4.15.0-1108.122 —
Ubuntu 18.04 LTS linux-gcp-5.4 5.4.0-1051.55~18.04.1 —
Ubuntu 18.04 LTS linux-hwe-5.4 5.4.0-81.91~18.04.1 —
Ubuntu 18.04 LTS linux-kvm 4.15.0-1099.101 —
Ubuntu 18.04 LTS linux-oracle 4.15.0-1080.88 —
Ubuntu 18.04 LTS linux-oracle-5.4 5.4.0-1053.57~18.04.1 —
Ubuntu 18.04 LTS linux-raspi-5.4 5.4.0-1042.46~18.04.3 —
Ubuntu 16.04 LTS linux-hwe-edge No fix yet —
Show 6 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu Pro FIPS 20.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro FIPS 18.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro FIPS-updates 20.04 LTS linux-aws-fips 5.4.0-1069.73+fips2 —
Ubuntu Pro FIPS-updates 20.04 LTS linux-azure-fips 5.4.0-1073.76+fips1 —
Ubuntu Pro FIPS-updates 20.04 LTS linux-fips 5.4.0-1032.37 —
Ubuntu Pro FIPS-updates 20.04 LTS linux-gcp-fips 5.4.0-1067.71~20.04.1 —
Ubuntu Pro FIPS-updates 18.04 LTS linux-aws-fips 4.15.0-2053.55 —
Ubuntu Pro FIPS-updates 18.04 LTS linux-azure-fips 4.15.0-2035.39 —
Ubuntu Pro FIPS-updates 18.04 LTS linux-fips 4.15.0-1069.78 —
Ubuntu Pro FIPS-updates 18.04 LTS linux-gcp-fips 4.15.0-2018.20 —
Ubuntu Pro 16.04 LTS linux-aws-hwe 4.15.0-1111.118~16.04.1 —
Ubuntu Pro 16.04 LTS linux-azure 4.15.0-1123.136~16.04.1 —
Ubuntu Pro 16.04 LTS linux-gcp 4.15.0-1108.122~16.04.1 —
Ubuntu Pro 16.04 LTS linux-hwe 4.15.0-156.163~16.04.1 —
Ubuntu Pro 16.04 LTS linux-oracle 4.15.0-1080.88~16.04.1 —
Ubuntu Pro 14.04 LTS linux-azure 4.15.0-1123.136~14.04.1 —

SUSE

Security tracker ↗
ReleasePackageFixed inAdvisory
SLES 15 SP3 kernel-64kb +7 5.3.18-150300.59.201.1 SUSE-SU-2025:1263-1
SLES 15 SP3 kernel-default-base 5.3.18-150300.59.201.1.150300.18.120.1 SUSE-SU-2025:1263-1
SLES 12 SP5 kernel-azure +2 4.12.14-16.188.1 SUSE-SU-2024:1979-1
SLES 12 SP5 kernel-docs +4 4.12.14-122.219.1 SUSE-SU-2024:2184-1
Show 9 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
SLES for SAP 15 SP3 kernel-default-base 5.3.18-150300.59.201.1.150300.18.120.1 SUSE-SU-2025:1263-1
SLES for SAP 15 SP3 kernel-docs +5 5.3.18-150300.59.201.1 SUSE-SU-2025:1263-1
SLES for SAP 12 SP5 kernel-azure +2 4.12.14-16.188.1 SUSE-SU-2024:1979-1
SLES for SAP 12 SP5 kernel-syms +2 4.12.14-122.219.1 SUSE-SU-2024:2184-1
SLE Real Time 12 SP5 kernel-rt +3 4.12.14-10.188.1 SUSE-SU-2024:1983-1
SLE Micro 5.2 kernel-default 5.3.18-150300.59.201.1 SUSE-SU-2025:1263-1
SLE Micro 5.2 kernel-default-base 5.3.18-150300.59.201.1.150300.18.120.1 SUSE-SU-2025:1263-1
SLE Micro 5.2 kernel-rt +1 5.3.18-150300.205.1 SUSE-SU-2025:1194-1
SLE Micro 5.1 kernel-default 5.3.18-150300.59.201.1 SUSE-SU-2025:1263-1
SLE Micro 5.1 kernel-default-base 5.3.18-150300.59.201.1.150300.18.120.1 SUSE-SU-2025:1263-1
SLE Micro 5.1 kernel-rt +1 5.3.18-150300.205.1 SUSE-SU-2025:1194-1
SLE Live Patching 15 SP3 kernel-default 5.3.18-150300.59.201.1 SUSE-SU-2025:1263-1
SLE Live Patching 15 SP3 kernel-livepatch-SLE15-SP3_Update_56 1-150300.7.3.1 SUSE-SU-2025:1263-1
SLE Live Patching 12 SP5 kernel-default 4.12.14-122.219.1 SUSE-SU-2024:2184-1
SLE Live Patching 12 SP5 kgraft-patch-SLE12-SP5_Update_57 1-8.3.1 SUSE-SU-2024:2184-1
SLE HPC 15 SP3 kernel-64kb +6 5.3.18-150300.59.201.1 SUSE-SU-2025:1263-1
SLE HPC 15 SP3 kernel-default-base 5.3.18-150300.59.201.1.150300.18.120.1 SUSE-SU-2025:1263-1
SUSE Enterprise Storage 7.1 kernel-64kb +6 5.3.18-150300.59.201.1 SUSE-SU-2025:1263-1
SUSE Enterprise Storage 7.1 kernel-default-base 5.3.18-150300.59.201.1.150300.18.120.1 SUSE-SU-2025:1263-1

Amazon Linux

ReleasePackageFixed inAdvisory
Amazon Linux 2 kernel-livepatch-4.14.238-182.421 1.0-0.amzn2 ALAS2-2021-1685
Amazon Linux 2 perf +8 4.14.238-182.421.amzn2 ALAS2-2021-1685

Advisories 6

References