Description
In the Linux kernel, the following vulnerability has been resolved:
nfsd: provide locking for v4_end_grace
Writing to v4_end_grace can race with server shutdown and result in
memory being accessed after it was freed - reclaim_str_hashtbl in
particularly.
We cannot hold nfsd_mutex across the nfsd4_end_grace() call as that is
held while client_tracking_op->init() is called and that can wait for
an upcall to nfsdcltrack which can write to v4_end_grace, resulting in a
deadlock.
nfsd4_end_grace() is also called by the landromat work queue and this
doesn't require locking as server shutdown will stop the work and wait
for it before freeing anything that nfsd4_end_grace() might access.
However, we must be sure that writing to v4_end_grace doesn't restart
the work item after shutdown has already waited for it. For this we
add a new flag protected with nn->client_lock. It is set only while it
is safe to make client tracking calls, and v4_end_grace only schedules
work while the flag is set with the spinlock held.
So this patch adds a nfsd_net field "client_tracking_active" which is
set as described. Another field "grace_end_forced", is set when
v4_end_grace is written. After this is set, and providing
client_tracking_active is set, the laundromat is scheduled.
This "grace_end_forced" field bypasses other checks for whether the
grace period has finished.
This resolves a race which can result in use-after-free.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Linux | Linux | 3.18 | 5.10.248 |
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 ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | linux | 6.18.8-1 | — |
| Debian 13 | linux | 6.12.69-1 | DSA-6126-1 |
| Debian 12 | linux | 6.1.162-1 | DSA-6127-1 |
| Debian 11 | linux | 5.10.249-1 | DLA-4475-1 |
| Debian 11 | linux-6.1 | 6.1.162-1~deb11u1 | DLA-4476-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Nvidia-BlueField 24.04 LTS | linux-bluefield | 6.8.0-1022.26 | — |
| Ubuntu Nvidia-BlueField 22.04 LTS | linux-bluefield | 5.15.0-1086.88 | — |
| Ubuntu 25.10 | linux +8 | No fix yet | — |
| Ubuntu 24.04 LTS | linux | 6.8.0-117.117 | USN-8278-1 |
| Ubuntu 24.04 LTS | linux-aws | 6.8.0-1055.58 | USN-8278-1 |
| Ubuntu 24.04 LTS | linux-azure | 6.8.0-1056.62 | USN-8278-2 |
| Ubuntu 24.04 LTS | linux-azure-6.17 | 6.17.0-1021.21~24.04.1 | USN-8604-1 |
| Ubuntu 24.04 LTS | linux-azure-fde | 6.8.0-1058.65 | — |
| Ubuntu 24.04 LTS | linux-azure-fde-6.17 | 6.17.0-1018.18~24.04.1 | USN-8605-1 |
| Ubuntu 24.04 LTS | linux-azure-nvidia | 6.8.0-1039.42 | — |
| Ubuntu 24.04 LTS | linux-gcp | 6.8.0-1058.61 | USN-8278-1 |
| Ubuntu 24.04 LTS | linux-gcp-6.17 | 6.17.0-1021.24~24.04.1 | USN-8570-1 |
| Ubuntu 24.04 LTS | linux-gke | 6.8.0-1054.60 | USN-8278-1 |
| Ubuntu 24.04 LTS | linux-gkeop | 6.8.0-1041.44 | USN-8278-1 |
| Ubuntu 24.04 LTS | linux-hwe-6.17 | 6.17.0-41.41~24.04.1 | — |
| Ubuntu 24.04 LTS | linux-ibm | 6.8.0-1055.56 | USN-8278-1 |
| Ubuntu 24.04 LTS | linux-lowlatency | 6.8.0-117.117.1 | USN-8278-1 |
| Ubuntu 24.04 LTS | linux-nvidia | 6.8.0-1054.57 | USN-8289-1 |
| Ubuntu 24.04 LTS | linux-nvidia-6.17 | 6.17.0-1031.31 | USN-8669-1 |
| Ubuntu 24.04 LTS | linux-nvidia-lowlatency | 6.8.0-1054.57.1 | USN-8289-1 |
| Ubuntu 24.04 LTS | linux-nvidia-tegra | 6.8.0-1024.24 | USN-8296-2 |
| Ubuntu 24.04 LTS | linux-oem-6.17 | 6.17.0-1030.30 | USN-8594-1 |
| Ubuntu 24.04 LTS | linux-oracle | 6.8.0-1054.55 | — |
| Ubuntu 24.04 LTS | linux-oracle-6.17 | 6.17.0-1019.19~24.04.3 | USN-8570-2 |
| Ubuntu 24.04 LTS | linux-raspi | 6.8.0-1056.60 | USN-8278-1 |
| Ubuntu 24.04 LTS | linux-riscv +20 | No fix yet | — |
| Ubuntu 24.04 LTS | linux-xilinx | 6.8.0-1032.33 | USN-8499-1 |
| Ubuntu 22.04 LTS | linux +1 | 5.15.0-173.183 | USN-8096-1 |
| Ubuntu 22.04 LTS | linux-aws | 5.15.0-1103.110 | USN-8096-1 |
| Ubuntu 22.04 LTS | linux-aws-6.8 | 6.8.0-1057.60~22.04.1 | — |
| Ubuntu 22.04 LTS | linux-azure | 5.15.0-1109.118 | USN-8163-2 |
| Ubuntu 22.04 LTS | linux-azure-6.8 | 6.8.0-1059.65~22.04.1 | USN-8440-1 |
| Ubuntu 22.04 LTS | linux-azure-fde | 5.15.0-1109.118.1 | — |
| Ubuntu 22.04 LTS | linux-azure-fde-6.8 | 6.8.0-1058.65~22.04.1 | — |
| Ubuntu 22.04 LTS | linux-gcp | 5.15.0-1103.112 | USN-8096-1 |
| Ubuntu 22.04 LTS | linux-gcp-6.8 | 6.8.0-1060.63~22.04.1 | — |
| Ubuntu 22.04 LTS | linux-gke | 5.15.0-1099.105 | USN-8096-3 |
| Ubuntu 22.04 LTS | linux-gkeop | 5.15.0-1086.94 | USN-8096-1 |
| Ubuntu 22.04 LTS | linux-hwe-6.8 | 6.8.0-124.124~22.04.1 | — |
| Ubuntu 22.04 LTS | linux-ibm +1 | 5.15.0-1097.100 | USN-8141-1, USN-8096-1 |
| Ubuntu 22.04 LTS | linux-ibm-6.8 | 6.8.0-1055.56~22.04.1 | USN-8278-1 |
| Ubuntu 22.04 LTS | linux-intel-iotg | 5.15.0-1098.104 | USN-8096-1 |
| Ubuntu 22.04 LTS | linux-kvm | 5.15.0-1095.100 | USN-8096-1 |
| Ubuntu 22.04 LTS | linux-lowlatency-hwe-6.8 | 6.8.0-117.117.1~22.04.1 | USN-8278-1 |
| Ubuntu 22.04 LTS | linux-nvidia | 5.15.0-1098.99 | USN-8096-1 |
| Ubuntu 22.04 LTS | linux-nvidia-6.8 | 6.8.0-1054.57~22.04.1 | USN-8289-2 |
| Ubuntu 22.04 LTS | linux-nvidia-tegra | 5.15.0-1055.55 | USN-8096-1 |
| Ubuntu 22.04 LTS | linux-nvidia-tegra-igx | 5.15.0-1044.44 | USN-8096-5 |
| Ubuntu 22.04 LTS | linux-oracle | 5.15.0-1100.106 | USN-8096-1 |
| Ubuntu 22.04 LTS | linux-oracle-6.8 | 6.8.0-1054.55~22.04.1 | — |
| Ubuntu 22.04 LTS | linux-riscv +32 | No fix yet | — |
| Ubuntu 22.04 LTS | linux-riscv-6.8 | 6.8.0-117.117~22.04.1 | — |
| Ubuntu 22.04 LTS | linux-xilinx-zynqmp | 5.15.0-1067.71 | USN-8096-1 |
Show 18 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | linux-gke +28 | No fix yet | — |
| Ubuntu 18.04 LTS | linux-gcp +14 | No fix yet | — |
| Ubuntu 16.04 LTS | linux-hwe-edge | No fix yet | — |
| Ubuntu Pro Realtime 24.04 LTS | linux-raspi-realtime | 6.8.0-2045.46 | USN-8278-1 |
| Ubuntu Pro Realtime 24.04 LTS | linux-realtime | 6.8.1-1051.52 | USN-8278-1 |
| Ubuntu Pro Realtime 24.04 LTS | linux-realtime-6.14 | No fix yet | — |
| Ubuntu Pro Realtime 24.04 LTS | linux-realtime-6.17 | 6.17.0-1018.20~24.04.1 | USN-8570-1 |
| Ubuntu Pro Realtime 22.04 LTS | linux-intel-iot-realtime | 5.15.0-1094.96 | USN-8116-1 |
| Ubuntu Pro Realtime 22.04 LTS | linux-realtime | 5.15.0-1102.111 | USN-8096-4 |
| Ubuntu Pro Realtime 22.04 LTS | linux-realtime-6.8 | 6.8.1-1051.52~22.04.1 | USN-8278-1 |
| 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 24.04 LTS | linux-aws-fips | 6.8.0-1055.58+fips1 | USN-8278-1 |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-azure-fips | 6.8.0-1059.65+fips1 | USN-8393-1 |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-fips | 6.8.0-116.116+fips1 | USN-8296-1 |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-gcp-fips | 6.8.0-1058.61+fips1 | USN-8278-1 |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-aws-fips | 5.15.0-1103.110+fips1 | USN-8096-2 |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-azure-fips | 5.15.0-1109.118+fips1 | USN-8163-1 |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-fips | 5.15.0-173.183+fips1 | USN-8096-2 |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-gcp-fips | 5.15.0-1103.112+fips1 | USN-8096-2 |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro FIPS-updates 18.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro FIPS-updates 16.04 LTS | linux-fips | No fix yet | — |
| Ubuntu Pro FIPS-preview 22.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro 20.04 LTS | linux +10 | No fix yet | — |
| Ubuntu Pro 20.04 LTS | linux-aws-5.15 | 5.15.0-1103.110~20.04.1 | USN-8096-3 |
| Ubuntu Pro 20.04 LTS | linux-azure-5.15 | 5.15.0-1110.119~20.04.1 | USN-8243-1 |
| Ubuntu Pro 20.04 LTS | linux-gcp-5.15 | 5.15.0-1103.112~20.04.1 | USN-8096-3 |
| Ubuntu Pro 20.04 LTS | linux-hwe-5.15 +1 | 5.15.0-173.183~20.04.1 | USN-8096-3 |
| Ubuntu Pro 20.04 LTS | linux-ibm-5.15 | 5.15.0-1097.100~20.04.1 | USN-8096-1 |
| Ubuntu Pro 20.04 LTS | linux-intel-iotg-5.15 | 5.15.0-1098.104~20.04.1 | USN-8096-3 |
| Ubuntu Pro 20.04 LTS | linux-nvidia-tegra-5.15 | 5.15.0-1055.55~20.04.1 | USN-8096-1 |
| Ubuntu Pro 20.04 LTS | linux-oracle-5.15 | 5.15.0-1100.106~20.04.1 | USN-8096-3 |
| Ubuntu Pro 20.04 LTS | linux-riscv-5.15 | 5.15.0-1097.101~20.04.1 | — |
| Ubuntu Pro 18.04 LTS | linux +12 | No fix yet | — |
| Ubuntu Pro 16.04 LTS | linux +7 | No fix yet | — |
| Ubuntu Pro 14.04 LTS | linux-aws +2 | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | kernel-64kb +8 | 6.12.0-160000.27.1 | SUSE-SU-2026:20931-1 |
| SLES for SAP 16.0 | kernel-default-base | 6.12.0-160000.27.1.160000.2.8 | SUSE-SU-2026:20931-1 |
| SLES 16.0 | kernel-64kb +8 | 6.12.0-160000.27.1 | SUSE-SU-2026:20931-1 |
| SLES 16.0 | kernel-default-base | 6.12.0-160000.27.1.160000.2.8 | SUSE-SU-2026:20931-1 |
| SLE Micro 6.2 | kernel-default-base | 6.12.0-160000.27.1.160000.2.8 | SUSE-SU-2026:20838-1 |
| SLE Micro 6.2 | kernel-rt +5 | 6.12.0-160000.27.1 | SUSE-SU-2026:20873-1, SUSE-SU-2026:20838-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 16.0 | kernel-default-base | 6.12.0-160000.27.1.160000.2.8 | openSUSE-SU-2026:20416-1 |
| openSUSE Leap 16.0 | kernel-rt +11 | 6.12.0-160000.27.1 | openSUSE-SU-2026:20416-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | kernel-livepatch-6.12.66-88.122 +1 | 1:1.0-0.amzn2023 | ALAS2023-2026-1494, ALAS2023-2026-1488 |
| Amazon Linux 2023 | perf +14 | 1:6.1.161-183.298.amzn2023 | ALAS2023-2026-1494 |
| Amazon Linux 2023 | perf6.12 +14 | 1:6.12.66-88.122.amzn2023 | ALAS2023-2026-1488 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 2 (CBL-Mariner) | kernel | 5.15.200.1-1 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 9 | kernel-uek +34 | 6.12.0-109.67.6.el10uek | ELSA-2026-50144 |
| Oracle Linux 8 | bpftool +18 | 5.15.0-318.199.3.2.el9uek | ELSA-2026-50145 |
Advisories 42
- SSA-457936 SSA-457936: Vulnerabilities in the additional GNU/Linux subsystem of the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP V3.1.7 Siemens ProductCERT · Nov 10, 2026
- USN-8604-1 linux-azure-6.17 vulnerabilities Ubuntu Security Notices (USN) · Nov 7, 2026
- USN-8440-1 linux-azure-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 7, 2026
- USN-8499-1 linux-xilinx vulnerabilities Ubuntu Security Notices (USN) · Nov 7, 2026
- USN-8393-1 linux-azure-fips vulnerabilities Ubuntu Security Notices (USN) · Nov 7, 2026
- USN-8669-1 linux-nvidia-6.17 vulnerabilities Ubuntu Security Notices (USN) · Nov 6, 2026
- USN-8570-1 linux-gcp-6.17, linux-realtime-6.17 vulnerabilities Ubuntu Security Notices (USN) · Nov 6, 2026
- USN-8570-2 linux-oracle-6.17 vulnerabilities Ubuntu Security Notices (USN) · Nov 6, 2026
- USN-8594-1 linux-oem-6.17 vulnerabilities Ubuntu Security Notices (USN) · Nov 6, 2026
- USN-8278-1 linux, linux-aws, linux-aws-fips, linux-gcp, linux-gcp-fips, linux-gke, linux-gkeop, linux-ibm, linux-ibm-6.8, linux-lowlatency, linux-lowlatency-hwe-6.8, linux-raspi, linux-raspi-realtime, linux-realtime, linux-realtime-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 5, 2026
- USN-8289-1 linux-nvidia, linux-nvidia-lowlatency vulnerabilities Ubuntu Security Notices (USN) · Nov 5, 2026
- USN-8289-2 linux-nvidia-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 5, 2026
- USN-8278-2 linux-azure vulnerabilities Ubuntu Security Notices (USN) · Nov 5, 2026
- USN-8096-1 linux, linux-aws, linux-gcp, linux-gkeop, linux-ibm, linux-ibm-5.15, linux-intel-iotg, linux-kvm, linux-lowlatency, linux-nvidia, linux-nvidia-tegra, linux-nvidia-tegra-5.15, linux-oracle, linux-xilinx-zynqmp vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- USN-8296-1 linux-fips vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- USN-8296-2 linux-nvidia-tegra vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- USN-8243-1 linux-azure-5.15 vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- USN-8096-3 linux-aws-5.15, linux-gcp-5.15, linux-gke, linux-hwe-5.15, linux-intel-iotg-5.15, linux-lowlatency-hwe-5.15, linux-oracle-5.15 vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- USN-8116-1 linux-intel-iot-realtime vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- USN-8096-2 linux-fips, linux-aws-fips, linux-gcp-fips vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- USN-8163-1 linux-azure-fips vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- USN-8141-1 linux-raspi vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- USN-8163-2 linux-azure vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- USN-8096-5 linux-nvidia-tegra-igx vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- USN-8096-4 linux-realtime vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- WID-SEC-2026-0215 Linux Kernel: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 2, 2026
- ICSA-26-295-11 Siemens SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP CISA ICS & IT advisories · Oct 22, 2026
- USN-8605-1 linux-azure-fde-6.17 vulnerabilities Ubuntu Security Notices (USN) · Oct 17, 2026
- SSA-019113 SSA-019113: Vulnerabilities in the additional GNU/Linux subsystem of the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP V3.1.6 Siemens ProductCERT · Oct 13, 2026
- ICSA-26-209-04 Siemens SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP CISA ICS & IT advisories · Jul 28, 2026
- SUSE-SU-2026:20873-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Jul 9, 2026
- SUSE-SU-2026:20931-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Apr 2, 2026
- openSUSE-SU-2026:20416-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 29, 2026
- SUSE-SU-2026:20838-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 28, 2026
- ALAS2023-2026-1494 Important: kernel security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Mar 27, 2026
- ALAS2023-2026-1488 Important: kernel6.12 security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Mar 27, 2026
- ELSA-2026-50144 Important: Unbreakable Enterprise kernel security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Mar 10, 2026
- ELSA-2026-50145 Important: Unbreakable Enterprise kernel security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Mar 10, 2026
- DSA-6127-1 linux - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-6126-1 linux - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-4475-1 linux - security update Debian Security (DSA / DLA) · Feb 10, 2026
- DLA-4476-1 linux-6.1 - security update Debian Security (DSA / DLA) · Feb 10, 2026
References
- https://git.kernel.org/stable/c/ca97360860eb02e3ae4ba42c19b439a0fcecbf06
- https://git.kernel.org/stable/c/e8bfa2401d4c51eca6e48e9b33c798828ca9df61
- https://git.kernel.org/stable/c/34eb22836e0cdba093baac66599d68c4cd245a9d
- https://git.kernel.org/stable/c/06600719d0f7a723811c45e4d51f5b742f345309
- https://git.kernel.org/stable/c/ba4811c8b433bfa681729ca42cc62b6034f223b0
- https://git.kernel.org/stable/c/53f07d095e7e680c5e4569a55a019f2c0348cdc6
- https://git.kernel.org/stable/c/2857bd59feb63fcf40fe4baf55401baea6b4feb4