Skip to content
OpenAdvisories
Critical · 9.8 CVE-2021-47506 EUVD-2021-34510

nfsd: fix use-after-free due to delegation race

Published May 24, 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-ibm Package: linux-ibm-5.4 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-lts-xenial 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:

nfsd: fix use-after-free due to delegation race

A delegation break could arrive as soon as we've called vfs_setlease. A
delegation break runs a callback which immediately (in
nfsd4_cb_recall_prepare) adds the delegation to del_recall_lru. If we
then exit nfs4_set_delegation without hashing the delegation, it will be
freed as soon as the callback is done with it, without ever being
removed from del_recall_lru.

Symptoms show up later as use-after-free or list corruption warnings,
usually in the laundromat thread.

I suspect aba2072f4523 "nfsd: grant read delegations to clients holding
writes" made this bug easier to hit, but I looked as far back as v3.0
and it looks to me it already had the same problem. So I'm not sure
where the bug was introduced; it may have been there from the beginning.

Affected products

VendorProductAffectedFixed
Linux Linux 3.17 4.4.296

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 5.15.15-1 —
Debian 13 linux 5.15.15-1 —
Debian 12 linux 5.15.15-1 —
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 5.4.0-105.119 —
Ubuntu 20.04 LTS linux-aws 5.4.0-1069.73 —
Ubuntu 20.04 LTS linux-azure 5.4.0-1073.76 —
Ubuntu 20.04 LTS linux-bluefield 5.4.0-1032.35 —
Ubuntu 20.04 LTS linux-gcp 5.4.0-1068.72 —
Ubuntu 20.04 LTS linux-gke +26 No fix yet —
Ubuntu 20.04 LTS linux-gkeop 5.4.0-1037.38 —
Ubuntu 20.04 LTS linux-ibm 5.4.0-1018.20 —
Ubuntu 20.04 LTS linux-kvm 5.4.0-1059.62 —
Ubuntu 20.04 LTS linux-oracle 5.4.0-1067.72 —
Ubuntu 20.04 LTS linux-raspi 5.4.0-1056.63 —
Ubuntu 18.04 LTS linux 4.15.0-169.177 —
Ubuntu 18.04 LTS linux-aws 4.15.0-1121.129 —
Ubuntu 18.04 LTS linux-aws-5.4 5.4.0-1069.73~18.04.1 —
Ubuntu 18.04 LTS linux-azure-4.15 4.15.0-1131.144 —
Ubuntu 18.04 LTS linux-azure-5.4 5.4.0-1073.76~18.04.1 —
Ubuntu 18.04 LTS linux-gcp +14 No fix yet —
Ubuntu 18.04 LTS linux-gcp-4.15 4.15.0-1116.130 —
Ubuntu 18.04 LTS linux-gcp-5.4 5.4.0-1068.72~18.04.1 —
Ubuntu 18.04 LTS linux-hwe-5.4 5.4.0-105.119~18.04.1 —
Ubuntu 18.04 LTS linux-ibm-5.4 5.4.0-1018.20~18.04.1 —
Ubuntu 18.04 LTS linux-kvm 4.15.0-1107.109 —
Ubuntu 18.04 LTS linux-oracle 4.15.0-1087.95 —
Ubuntu 18.04 LTS linux-oracle-5.4 5.4.0-1067.72~18.04.1 —
Ubuntu 18.04 LTS linux-raspi-5.4 5.4.0-1056.63~18.04.1 —
Ubuntu 16.04 LTS linux-hwe-edge No fix yet —
Show 12 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 16.04 LTS linux-fips 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 5.4.0-1046.52 —
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 4.15.0-2061.63 —
Ubuntu Pro FIPS-updates 18.04 LTS linux-azure-fips 4.15.0-2043.47 —
Ubuntu Pro FIPS-updates 18.04 LTS linux-fips 4.15.0-1078.87 —
Ubuntu Pro FIPS-updates 18.04 LTS linux-gcp-fips 4.15.0-2026.28 —
Ubuntu Pro FIPS-updates 16.04 LTS linux-fips 4.4.0-1113.120 USN-7506-3
Ubuntu Pro 24.04 LTS linux 6.8.0-59.61 LSN-0112-1
Ubuntu Pro 24.04 LTS linux-aws 6.8.0-1028.30 LSN-0112-1
Ubuntu Pro 24.04 LTS linux-azure 6.8.0-1028.33 LSN-0112-1
Ubuntu Pro 24.04 LTS linux-gcp 6.8.0-1029.31 LSN-0112-1
Ubuntu Pro 24.04 LTS linux-ibm 6.8.0-1025.25 LSN-0112-1
Ubuntu Pro 24.04 LTS linux-oracle 6.8.0-1025.26 LSN-0112-1
Ubuntu Pro 22.04 LTS linux 5.15.0-141.151 LSN-0112-1
Ubuntu Pro 22.04 LTS linux-aws 5.15.0-1085.92 LSN-0112-1
Ubuntu Pro 22.04 LTS linux-azure 5.15.0-1090.99 LSN-0112-1
Ubuntu Pro 22.04 LTS linux-gcp 5.15.0-1084.93 LSN-0112-1
Ubuntu Pro 22.04 LTS linux-gke +1 5.15.0-1082.88 LSN-0112-1
Ubuntu Pro 22.04 LTS linux-ibm 5.15.0-1077.80 LSN-0112-1
Ubuntu Pro 20.04 LTS linux 5.4.0-218.238 LSN-0112-1
Ubuntu Pro 20.04 LTS linux-aws 5.4.0-1147.157 LSN-0112-1
Ubuntu Pro 20.04 LTS linux-aws-5.15 5.15.0-1086.93~20.04.1 LSN-0112-1
Ubuntu Pro 20.04 LTS linux-azure 5.4.0-1152.159 LSN-0112-1
Ubuntu Pro 20.04 LTS linux-azure-5.15 5.15.0-1091.100~20.04.1 LSN-0112-1
Ubuntu Pro 20.04 LTS linux-gcp 5.4.0-1150.159 LSN-0112-1
Ubuntu Pro 20.04 LTS linux-gcp-5.15 5.15.0-1085.94~20.04.1 LSN-0112-1
Ubuntu Pro 20.04 LTS linux-gkeop 5.4.0-1037.38 LSN-0112-1
Ubuntu Pro 20.04 LTS linux-hwe-5.15 +1 5.15.0-142.152~20.04.1 LSN-0112-1
Ubuntu Pro 20.04 LTS linux-ibm 5.4.0-1093.98 LSN-0112-1
Ubuntu Pro 20.04 LTS linux-ibm-5.15 5.15.0-1078.81~20.04.1 LSN-0112-1
Ubuntu Pro 20.04 LTS linux-oracle 5.4.0-1145.155 LSN-0112-1
Ubuntu Pro 20.04 LTS linux-oracle-5.15 5.15.0-1083.89~20.04.1 LSN-0112-1
Ubuntu Pro 18.04 LTS linux 4.15.0-247.259 LSN-0112-1
Ubuntu Pro 18.04 LTS linux-aws 4.15.0-1189.202 LSN-0112-1
Ubuntu Pro 18.04 LTS linux-azure-4.15 4.15.0-1197.212 LSN-0112-1
Ubuntu Pro 18.04 LTS linux-gcp-4.15 4.15.0-1182.199 LSN-0112-1
Ubuntu Pro 18.04 LTS linux-hwe-5.4 5.4.0-218.238~18.04.1 LSN-0112-1
Ubuntu Pro 18.04 LTS linux-oracle 4.15.0-1151.162 LSN-0112-1
Ubuntu Pro 16.04 LTS linux 4.4.0-268.302 USN-7506-1, LSN-0112-1
Ubuntu Pro 16.04 LTS linux-aws 4.4.0-1181.196 USN-7506-1, LSN-0112-1
Ubuntu Pro 16.04 LTS linux-aws-hwe 4.15.0-1120.128~16.04.1 LSN-0112-1
Ubuntu Pro 16.04 LTS linux-azure 4.15.0-1131.144~16.04.1 LSN-0112-1
Ubuntu Pro 16.04 LTS linux-gcp 4.15.0-1116.130~16.04.1 LSN-0112-1
Ubuntu Pro 16.04 LTS linux-hwe 4.15.0-169.177~16.04.1 LSN-0112-1
Ubuntu Pro 16.04 LTS linux-kvm 4.4.0-1144.155 USN-7506-1
Ubuntu Pro 16.04 LTS linux-oracle 4.15.0-1087.95~16.04.1 —
Ubuntu Pro 14.04 LTS linux No fix yet —
Ubuntu Pro 14.04 LTS linux-aws 4.4.0-1143.149 USN-7506-2
Ubuntu Pro 14.04 LTS linux-azure 4.15.0-1131.144~14.04.1 —
Ubuntu Pro 14.04 LTS linux-lts-xenial 4.4.0-268.302~14.04.1 USN-7506-4
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
SLES 15 SP3 kernel-64kb +7 5.3.18-150300.59.164.1 SUSE-SU-2024:2948-1, SUSE-SU-2024:2185-1
SLES 15 SP3 kernel-default-base 5.3.18-150300.59.164.1.150300.18.96.1 SUSE-SU-2024:2948-1, SUSE-SU-2024:2185-1
SLES 15 SP2 kernel-default-base 5.3.18-150200.24.194.1.150200.9.99.1 SUSE-SU-2024:2923-1, SUSE-SU-2024:2183-1
SLES 15 SP2 kernel-docs +5 5.3.18-150200.24.194.1 SUSE-SU-2024:2923-1, SUSE-SU-2024:2183-1
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 22 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
SLES for SAP 15 SP3 kernel-default-base 5.3.18-150300.59.164.1.150300.18.96.1 SUSE-SU-2024:2948-1, SUSE-SU-2024:2185-1
SLES for SAP 15 SP3 kernel-docs +5 5.3.18-150300.59.164.1 SUSE-SU-2024:2948-1, SUSE-SU-2024:2185-1
SLES for SAP 15 SP2 kernel-default-base 5.3.18-150200.24.194.1.150200.9.99.1 SUSE-SU-2024:2923-1, SUSE-SU-2024:2183-1
SLES for SAP 15 SP2 kernel-docs +5 5.3.18-150200.24.194.1 SUSE-SU-2024:2923-1, SUSE-SU-2024:2183-1
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 5.5 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 Micro 5.2 kernel-default 5.3.18-150300.59.164.1 SUSE-SU-2024:2948-1, SUSE-SU-2024:2185-1
SLE Micro 5.2 kernel-default-base 5.3.18-150300.59.164.1.150300.18.96.1 SUSE-SU-2024:2948-1, SUSE-SU-2024:2185-1
SLE Micro 5.2 kernel-rt +1 5.3.18-150300.172.1 SUSE-SU-2024:2010-1
SLE Micro 5.1 kernel-default 5.3.18-150300.59.164.1 SUSE-SU-2024:2948-1, SUSE-SU-2024:2185-1
SLE Micro 5.1 kernel-default-base 5.3.18-150300.59.164.1.150300.18.96.1 SUSE-SU-2024:2948-1, SUSE-SU-2024:2185-1
SLE Micro 5.1 kernel-rt +1 5.3.18-150300.172.1 SUSE-SU-2024:2010-1
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 Live Patching 15 SP3 kernel-default 5.3.18-150300.59.164.1 SUSE-SU-2024:2948-1, SUSE-SU-2024:2185-1
SLE Live Patching 15 SP3 kernel-livepatch-SLE15-SP3_Update_45 +1 1-150300.7.3.1 SUSE-SU-2024:2948-1, SUSE-SU-2024:2185-1
SLE Live Patching 15 SP2 kernel-default 5.3.18-150200.24.194.1 SUSE-SU-2024:2923-1, SUSE-SU-2024:2183-1
SLE Live Patching 15 SP2 kernel-livepatch-SLE15-SP2_Update_49 +1 1-150200.5.3.1 SUSE-SU-2024:2923-1, SUSE-SU-2024:2183-1
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 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
SLE HPC 15 SP3 kernel-64kb +6 5.3.18-150300.59.164.1 SUSE-SU-2024:2948-1, SUSE-SU-2024:2185-1
SLE HPC 15 SP3 kernel-default-base 5.3.18-150300.59.164.1.150300.18.96.1 SUSE-SU-2024:2948-1, SUSE-SU-2024:2185-1
SLE HPC 15 SP2 kernel-default-base 5.3.18-150200.24.194.1.150200.9.99.1 SUSE-SU-2024:2923-1, SUSE-SU-2024:2183-1
SLE HPC 15 SP2 kernel-docs +5 5.3.18-150200.24.194.1 SUSE-SU-2024:2923-1, SUSE-SU-2024:2183-1
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
SUSE Enterprise Storage 7.1 kernel-64kb +6 5.3.18-150300.59.164.1 SUSE-SU-2024:2948-1, SUSE-SU-2024:2185-1
SUSE Enterprise Storage 7.1 kernel-default-base 5.3.18-150300.59.164.1.150300.18.96.1 SUSE-SU-2024:2948-1, SUSE-SU-2024:2185-1
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

Amazon Linux

ReleasePackageFixed inAdvisory
Amazon Linux 2 kernel-livepatch-4.14.262-200.489 1.0-0.amzn2 ALAS2-2022-1749
Amazon Linux 2 perf +8 4.14.262-200.489.amzn2 ALAS2-2022-1749

Advisories 20

References