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Critical · 9.8 CVE-2026-74493 EUVD-2026-59686GHSA-xhjj-46q7-2hx6

net/smc: fix socket use-after-free during link group termination

Published Aug 15, 2026 · Updated Oct 16, 2026 · Assigned by Linux

Vendor: Linux Product: Linux Package: kernel Package: linux Package: linux Package: linux-6.12 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-5.15 Package: linux-aws-5.19 Package: linux-aws-5.3 Package: linux-aws-5.8 Package: linux-aws-6.14 Package: linux-aws-6.17 Package: linux-aws-6.2 Package: linux-aws-6.5 Package: linux-aws-6.8 Package: linux-aws-7.0 Package: linux-aws-fips Package: linux-azure Package: linux-azure-5.11 Package: linux-azure-5.13 Package: linux-azure-5.15 Package: linux-azure-5.19 Package: linux-azure-5.3 Package: linux-azure-5.8 Package: linux-azure-6.11 Package: linux-azure-6.14 Package: linux-azure-6.17 Package: linux-azure-6.2 Package: linux-azure-6.5 Package: linux-azure-6.8 Package: linux-azure-7.0 Package: linux-azure-edge Package: linux-azure-fde Package: linux-azure-fde-5.15 Package: linux-azure-fde-5.19 Package: linux-azure-fde-6.14 Package: linux-azure-fde-6.17 Package: linux-azure-fde-6.2 Package: linux-azure-fde-6.8 Package: linux-azure-fde-7.0 Package: linux-azure-fips Package: linux-azure-nvidia Package: linux-azure-nvidia-6.14 Package: linux-bluefield Package: linux-fips Package: linux-gcp Package: linux-gcp-5.11 Package: linux-gcp-5.13 Package: linux-gcp-5.15 Package: linux-gcp-5.19 Package: linux-gcp-5.3 Package: linux-gcp-5.8 Package: linux-gcp-6.11 Package: linux-gcp-6.14 Package: linux-gcp-6.17 Package: linux-gcp-6.2 Package: linux-gcp-6.5 Package: linux-gcp-6.8 Package: linux-gcp-7.0 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-5.15 Package: linux-gkeop-5.4 Package: linux-hwe Package: linux-hwe-5.11 Package: linux-hwe-5.13 Package: linux-hwe-5.15 Package: linux-hwe-5.19 Package: linux-hwe-5.8 Package: linux-hwe-6.11 Package: linux-hwe-6.14 Package: linux-hwe-6.17 Package: linux-hwe-6.2 Package: linux-hwe-6.5 Package: linux-hwe-6.8 Package: linux-hwe-7.0 Package: linux-hwe-edge Package: linux-ibm Package: linux-ibm-5.15 Package: linux-ibm-6.8 Package: linux-intel-5.13 Package: linux-intel-iot-realtime Package: linux-intel-iotg Package: linux-intel-iotg-5.15 Package: linux-kvm Package: linux-lowlatency Package: linux-lowlatency-hwe-5.15 Package: linux-lowlatency-hwe-5.19 Package: linux-lowlatency-hwe-6.11 Package: linux-lowlatency-hwe-6.2 Package: linux-lowlatency-hwe-6.5 Package: linux-lowlatency-hwe-6.8 Package: linux-nvidia Package: linux-nvidia-6.11 Package: linux-nvidia-6.17 Package: linux-nvidia-6.2 Package: linux-nvidia-6.5 Package: linux-nvidia-6.8 Package: linux-nvidia-7.0 Package: linux-nvidia-bos Package: linux-nvidia-lowlatency Package: linux-nvidia-tegra Package: linux-nvidia-tegra-5.15 Package: linux-nvidia-tegra-igx 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-oem-6.11 Package: linux-oem-6.14 Package: linux-oem-6.17 Package: linux-oem-6.5 Package: linux-oem-6.8 Package: linux-oem-7.0 Package: linux-oracle Package: linux-oracle-5.0 Package: linux-oracle-5.11 Package: linux-oracle-5.13 Package: linux-oracle-5.15 Package: linux-oracle-5.3 Package: linux-oracle-5.8 Package: linux-oracle-6.14 Package: linux-oracle-6.17 Package: linux-oracle-6.5 Package: linux-oracle-6.8 Package: linux-oracle-7.0 Package: linux-raspi Package: linux-raspi-realtime Package: linux-raspi2 Package: linux-realtime Package: linux-realtime-6.14 Package: linux-realtime-6.17 Package: linux-realtime-6.8 Package: linux-riscv Package: linux-riscv-5.11 Package: linux-riscv-5.15 Package: linux-riscv-5.19 Package: linux-riscv-5.8 Package: linux-riscv-6.14 Package: linux-riscv-6.17 Package: linux-riscv-6.5 Package: linux-riscv-6.8 Package: linux-riscv-7.0 Package: linux-starfive-5.19 Package: linux-starfive-6.2 Package: linux-starfive-6.5 Package: linux-vmware Package: linux-xilinx Package: linux-xilinx-zynqmp Platform: Linux Ecosystem: Azure Linux Ecosystem: Debian Ecosystem: Ubuntu

Description

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

net/smc: fix socket use-after-free during link group termination

__smc_lgr_terminate() drops conns_lock after finding a connection in
lgr->conns_all, but before taking a reference on its socket. The connection
is embedded in the socket, and its registration reference protects it only
while the connection remains in the tree.

A concurrent close can unregister the connection and drop that reference,
freeing the socket before the termination worker reaches sock_hold().

The race is reachable when close overlaps link group termination.
Local stress testing reproduced the use-after-free and KASAN reported:

BUG: KASAN: slab-use-after-free in __smc_lgr_terminate.part.0 [smc]
Write of size 4 by task kworker/3:3
Workqueue: events smc_lgr_terminate_work [smc]
__smc_lgr_terminate.part.0 [smc]

The socket was allocated by smc_create(), freed through
slab_free_after_rcu_debug(), and was followed by:

refcount_t: addition on 0; use-after-free.
__smc_lgr_terminate.part.0 [smc]

Take the socket reference while conns_lock still protects the tree entry.
The unregister path then cannot drop the last reference until termination
has finished using the socket.

Affected products

VendorProductAffectedFixed
Linux Linux 5.5 5.10.265

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 7.1.8-1 —
Debian 13 linux 6.12.105-1 —
Debian 12 linux 6.1.187-1 —
Debian 12 linux-6.12 6.12.107-1~deb12u1 —
ReleasePackageFixed inAdvisory
Ubuntu Nvidia-BlueField 24.04 LTS linux-bluefield 6.8.0-1036.41 —
Ubuntu Nvidia-BlueField 22.04 LTS linux-bluefield 5.15.0-1101.103 —
Ubuntu 26.04 LTS linux 7.0.0-42.42 USN-8959-1
Ubuntu 26.04 LTS linux-aws 7.0.0-1016.17 USN-8959-1
Ubuntu 26.04 LTS linux-azure 7.0.0-1020.21 USN-9019-1
Ubuntu 26.04 LTS linux-azure-fde 7.0.0-1019.19 USN-9020-1
Ubuntu 26.04 LTS linux-gcp 7.0.0-1016.18 USN-8959-1
Ubuntu 26.04 LTS linux-gke 7.0.0-1010.11 USN-9020-1
Ubuntu 26.04 LTS linux-ibm +1 7.0.0-1017.17 USN-8960-1, USN-8959-1
Ubuntu 26.04 LTS linux-nvidia +1 No fix yet —
Ubuntu 26.04 LTS linux-oracle 7.0.0-1015.16 USN-8959-1
Ubuntu 26.04 LTS linux-raspi 7.0.0-1023.23 USN-9021-1
Ubuntu 26.04 LTS linux-realtime 7.0.0-43.43.1 USN-9020-1
Ubuntu 26.04 LTS linux-riscv 7.0.0-42.42.1 —
Ubuntu 24.04 LTS linux 6.8.0-149.149 USN-9022-1
Ubuntu 24.04 LTS linux-aws 6.8.0-1069.74 USN-9022-1
Ubuntu 24.04 LTS linux-aws-7.0 7.0.0-1017.18~24.04.1 USN-9020-1
Ubuntu 24.04 LTS linux-azure 6.8.0-1073.82 USN-9022-1
Ubuntu 24.04 LTS linux-azure-fde 6.8.0-1071.78 USN-9039-1
Ubuntu 24.04 LTS linux-azure-fde-7.0 7.0.0-1019.19~24.04.1 USN-9020-1
Ubuntu 24.04 LTS linux-gcp 6.8.0-1073.81 USN-9022-1
Ubuntu 24.04 LTS linux-gcp-7.0 7.0.0-1017.19~24.04.1 USN-9020-1
Ubuntu 24.04 LTS linux-gke 6.8.0-1068.77 USN-9022-1
Ubuntu 24.04 LTS linux-gkeop 6.8.0-1053.57 USN-9023-1
Ubuntu 24.04 LTS linux-hwe-7.0 7.0.0-42.42~24.04.1 USN-8959-1
Ubuntu 24.04 LTS linux-ibm 6.8.0-1069.70 USN-9022-1
Ubuntu 24.04 LTS linux-lowlatency 6.8.0-149.149.1 USN-9022-1
Ubuntu 24.04 LTS linux-nvidia 6.8.0-1067.70 USN-9024-1
Ubuntu 24.04 LTS linux-nvidia-lowlatency 6.8.0-1067.70.1 USN-9040-1
Ubuntu 24.04 LTS linux-nvidia-tegra 6.8.0-1035.38 USN-8781-1
Ubuntu 24.04 LTS linux-oracle 6.8.0-1067.71 USN-9022-1
Ubuntu 24.04 LTS linux-oracle-7.0 7.0.0-1016.18~24.04.1 USN-9020-1
Ubuntu 24.04 LTS linux-raspi 6.8.0-1068.72 USN-9025-1
Ubuntu 24.04 LTS linux-riscv +31 No fix yet —
Ubuntu 24.04 LTS linux-riscv-7.0 7.0.0-42.42.1~24.04.1 —
Ubuntu 24.04 LTS linux-vmware 6.8.0-1010.10 USN-9022-1
Ubuntu 22.04 LTS linux 5.15.0-198.208 USN-8875-1
Ubuntu 22.04 LTS linux-aws 5.15.0-1117.124 USN-8875-1
Ubuntu 22.04 LTS linux-aws-6.8 6.8.0-1069.74~22.04.1 USN-9024-1
Ubuntu 22.04 LTS linux-azure 5.15.0-1123.132 USN-8875-1
Ubuntu 22.04 LTS linux-azure-6.8 6.8.0-1073.82~22.04.1 USN-9026-1
Ubuntu 22.04 LTS linux-azure-fde 5.15.0-1122.131 USN-8876-1
Ubuntu 22.04 LTS linux-azure-fde-6.8 6.8.0-1071.78~22.04.1 USN-9026-1
Ubuntu 22.04 LTS linux-gcp 5.15.0-1118.128 USN-8877-1
Ubuntu 22.04 LTS linux-gcp-6.8 6.8.0-1073.81~22.04.1 USN-9024-1
Ubuntu 22.04 LTS linux-gke 5.15.0-1113.119 USN-8875-1
Ubuntu 22.04 LTS linux-gkeop 5.15.0-1100.108 USN-8875-1
Ubuntu 22.04 LTS linux-hwe-6.8 6.8.0-149.149~22.04.1 USN-9066-1
Ubuntu 22.04 LTS linux-ibm 5.15.0-1111.115 USN-8875-1
Ubuntu 22.04 LTS linux-ibm-6.8 6.8.0-1069.70~22.04.1 USN-9024-1
Ubuntu 22.04 LTS linux-intel-iotg 5.15.0-1112.118 USN-8875-1
Ubuntu 22.04 LTS linux-kvm 5.15.0-1109.114 USN-8875-1
Ubuntu 22.04 LTS linux-lowlatency 5.15.0-195.205 USN-8875-1
Ubuntu 22.04 LTS linux-lowlatency-hwe-6.8 6.8.0-149.149.1~22.04.1 USN-9024-1
Ubuntu 22.04 LTS linux-nvidia 5.15.0-1112.113 USN-8875-2
Ubuntu 22.04 LTS linux-nvidia-tegra 5.15.0-1070.72 USN-8963-1
Ubuntu 22.04 LTS linux-nvidia-tegra-igx 5.15.0-1059.59 USN-8963-1
Ubuntu 22.04 LTS linux-oracle 5.15.0-1114.120 USN-8875-1
Ubuntu 22.04 LTS linux-oracle-6.8 6.8.0-1067.71~22.04.1 USN-9025-1
Ubuntu 22.04 LTS linux-raspi 5.15.0-1113.116 USN-9029-1
Ubuntu 22.04 LTS linux-riscv +33 No fix yet —
Ubuntu 22.04 LTS linux-xilinx-zynqmp 5.15.0-1080.84 USN-8875-1
Show 9 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
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 6.8.0-2056.58 USN-9025-1
Ubuntu Pro Realtime 24.04 LTS linux-realtime 6.8.1-1064.65 USN-9023-1
Ubuntu Pro Realtime 24.04 LTS linux-realtime-6.14 +1 No fix yet —
Ubuntu Pro Realtime 22.04 LTS linux-intel-iot-realtime 5.15.0-1109.111 USN-8875-1
Ubuntu Pro Realtime 22.04 LTS linux-realtime 5.15.0-1116.125 USN-8875-1
Ubuntu Pro Realtime 22.04 LTS linux-realtime-6.8 6.8.1-1064.65~22.04.1 USN-9024-1
Ubuntu Pro FIPS-updates 24.04 LTS linux-aws-fips 6.8.0-1069.74+fips1 USN-9023-1
Ubuntu Pro FIPS-updates 24.04 LTS linux-azure-fips 6.8.0-1073.82+fips1 USN-9022-1
Ubuntu Pro FIPS-updates 24.04 LTS linux-fips No fix yet —
Ubuntu Pro FIPS-updates 24.04 LTS linux-gcp-fips 6.8.0-1073.81+fips1 USN-9023-1
Ubuntu Pro FIPS-updates 22.04 LTS linux-aws-fips 5.15.0-1117.124+fips1 USN-8875-1
Ubuntu Pro FIPS-updates 22.04 LTS linux-azure-fips 5.15.0-1123.132+fips1 USN-8875-1
Ubuntu Pro FIPS-updates 22.04 LTS linux-fips 5.15.0-198.208+fips1 USN-8875-1
Ubuntu Pro FIPS-updates 22.04 LTS linux-gcp-fips 5.15.0-1118.128+fips1 USN-8877-1
Ubuntu Pro FIPS-preview 22.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro 20.04 LTS linux-aws-5.15 5.15.0-1117.124~20.04.1 USN-8875-1
Ubuntu Pro 20.04 LTS linux-azure-5.15 5.15.0-1123.132~20.04.1 USN-8875-1
Ubuntu Pro 20.04 LTS linux-azure-fde-5.15 5.15.0-1122.131~20.04.1 USN-8875-1
Ubuntu Pro 20.04 LTS linux-gcp-5.15 5.15.0-1118.128~20.04.1 USN-8878-1
Ubuntu Pro 20.04 LTS linux-hwe-5.15 5.15.0-198.208~20.04.1 USN-8875-1
Ubuntu Pro 20.04 LTS linux-ibm-5.15 +1 5.15.0-1111.115~20.04.1 USN-8875-1
Ubuntu Pro 20.04 LTS linux-intel-iotg-5.15 5.15.0-1112.118~20.04.1 USN-8875-1
Ubuntu Pro 20.04 LTS linux-lowlatency-hwe-5.15 5.15.0-195.205~20.04.1 USN-8875-1
Ubuntu Pro 20.04 LTS linux-nvidia-tegra-5.15 5.15.0-1070.72~20.04.1 USN-8963-1
Ubuntu Pro 20.04 LTS linux-oracle-5.15 5.15.0-1114.120~20.04.1 USN-8879-1
ReleasePackageFixed inAdvisory
SLES 15 SP7 kernel-64kb +7 6.4.0-150700.53.84.1 SUSE-SU-2026:4706-1
SLES 15 SP7 kernel-default-base 6.4.0-150700.53.84.1.150700.17.47.1 SUSE-SU-2026:4706-1
SLES 15 SP6 kernel-64kb +6 6.4.0-150600.23.138.1 SUSE-SU-2026:4660-1
SLES 15 SP6 kernel-default-base 6.4.0-150600.23.138.1.150600.12.64.1 SUSE-SU-2026:4660-1
SLES 15 SP5 kernel-64kb +4 5.14.21-150500.55.192.2 SUSE-SU-2026:4667-1
SLES 15 SP5 kernel-default-base 5.14.21-150500.55.192.2.150500.6.89.2 SUSE-SU-2026:4667-1
SLES 15 SP5 kernel-docs +1 5.14.21-150500.55.192.1 SUSE-SU-2026:4667-1
SLES 15 SP4 kernel-64kb +6 5.14.21-150400.24.243.1 SUSE-SU-2026:4668-1
SLES 15 SP4 kernel-default-base 5.14.21-150400.24.243.1.150400.24.122.1 SUSE-SU-2026:4668-1
Show 18 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
SLES for SAP 16.0 kernel-64kb +8 6.12.0-160000.39.1 SUSE-SU-2026:24235-1
SLES for SAP 16.0 kernel-default-base 6.12.0-160000.39.1.160000.2.26 SUSE-SU-2026:24235-1
SLES for SAP 15 SP6 kernel-default-base 6.4.0-150600.23.138.1.150600.12.64.1 SUSE-SU-2026:4660-1
SLES for SAP 15 SP6 kernel-docs +4 6.4.0-150600.23.138.1 SUSE-SU-2026:4660-1
SLES for SAP 15 SP5 kernel-default-base 5.14.21-150500.55.192.2.150500.6.89.2 SUSE-SU-2026:4667-1
SLES for SAP 15 SP5 kernel-docs +1 5.14.21-150500.55.192.1 SUSE-SU-2026:4667-1
SLES for SAP 15 SP5 kernel-source +2 5.14.21-150500.55.192.2 SUSE-SU-2026:4667-1
SLES for SAP 15 SP4 kernel-default-base 5.14.21-150400.24.243.1.150400.24.122.1 SUSE-SU-2026:4668-1
SLES for SAP 15 SP4 kernel-docs +4 5.14.21-150400.24.243.1 SUSE-SU-2026:4668-1
SLES 16.0 kernel-64kb +8 6.12.0-160000.39.1 SUSE-SU-2026:24235-1, SUSE-SU-2026:24197-1
SLES 16.0 kernel-default-base 6.12.0-160000.39.1.160000.2.26 SUSE-SU-2026:24235-1
SLE Micro 6.2 kernel-default-base 6.12.0-160000.39.1.160000.2.26 SUSE-SU-2026:24184-1
SLE Micro 6.2 kernel-rt +5 6.12.0-160000.39.1 SUSE-SU-2026:24184-1, SUSE-SU-2026:24179-1
SLE Micro 6.2 podman 5.4.2-160000.6.1 SUSE-SU-2026:24182-1
SLE Micro 6.1 kernel-default-base 6.4.0-159998.53.1.159998.21.38 SUSE-SU-2026:24181-1
SLE Micro 6.1 kernel-rt +4 6.4.0-159998.53.1 SUSE-SU-2026:24182-1, SUSE-SU-2026:24181-1
SLE Micro 6.0 kernel-default-base 6.4.0-159998.53.1.159998.21.38 SUSE-SU-2026:24315-1
SLE Micro 6.0 kernel-rt +4 6.4.0-159998.53.1 SUSE-SU-2026:24316-1, SUSE-SU-2026:24315-1
SLE Micro 5.5 kernel-default-base 5.14.21-150500.55.192.2.150500.6.89.2 SUSE-SU-2026:4667-1
SLE Micro 5.5 kernel-rt +1 5.14.21-150500.13.164.1 SUSE-SU-2026:4665-1
SLE Micro 5.5 kernel-source +1 5.14.21-150500.55.192.2 SUSE-SU-2026:4667-1
SLE Micro 5.4 kernel-default-base 5.14.21-150400.24.243.1.150400.24.122.1 SUSE-SU-2026:4668-1
SLE Micro 5.4 kernel-rt +1 5.14.21-150400.15.189.1 SUSE-SU-2026:4666-1
SLE Micro 5.4 kernel-source +1 5.14.21-150400.24.243.1 SUSE-SU-2026:4668-1
SLE Micro 5.3 kernel-default-base 5.14.21-150400.24.243.1.150400.24.122.1 SUSE-SU-2026:4668-1
SLE Micro 5.3 kernel-rt +1 5.14.21-150400.15.189.1 SUSE-SU-2026:4666-1
SLE Micro 5.3 kernel-source +1 5.14.21-150400.24.243.1 SUSE-SU-2026:4668-1
SLE Live Patching 15 SP7 kernel-default 6.4.0-150700.53.84.1 SUSE-SU-2026:4706-1
SLE Live Patching 15 SP7 kernel-livepatch-SLE15-SP7-RT_Update_21 1-150700.1.3.1 SUSE-SU-2026:4640-1
SLE Live Patching 15 SP7 kernel-livepatch-SLE15-SP7_Update_22 1-150700.15.3.1 SUSE-SU-2026:4706-1
SLE Live Patching 15 SP6 kernel-default 6.4.0-150600.23.138.1 SUSE-SU-2026:4660-1
SLE Live Patching 15 SP6 kernel-livepatch-SLE15-SP6_Update_32 1-150600.13.3.1 SUSE-SU-2026:4660-1
SLE Live Patching 15 SP5 kernel-default 5.14.21-150500.55.192.2 SUSE-SU-2026:4667-1
SLE Live Patching 15 SP5 kernel-livepatch-SLE15-SP5_Update_46 1-150500.11.3.2 SUSE-SU-2026:4667-1
SLE Live Patching 15 SP4 kernel-default 5.14.21-150400.24.243.1 SUSE-SU-2026:4668-1
SLE Live Patching 15 SP4 kernel-livepatch-SLE15-SP4_Update_60 1-150400.9.3.1 SUSE-SU-2026:4668-1
SLE HPC 15 SP5 kernel-64kb +3 5.14.21-150500.55.192.2 SUSE-SU-2026:4667-1
SLE HPC 15 SP5 kernel-default-base 5.14.21-150500.55.192.2.150500.6.89.2 SUSE-SU-2026:4667-1
SLE HPC 15 SP5 kernel-docs +1 5.14.21-150500.55.192.1 SUSE-SU-2026:4667-1
SLE HPC 15 SP4 kernel-64kb +5 5.14.21-150400.24.243.1 SUSE-SU-2026:4668-1
SLE HPC 15 SP4 kernel-default-base 5.14.21-150400.24.243.1.150400.24.122.1 SUSE-SU-2026:4668-1
SUSE Real Time Module 15 SP7 kernel-rt +2 6.4.0-150700.7.78.1 SUSE-SU-2026:4640-1
ReleasePackageFixed inAdvisory
openSUSE Leap 16.0 kernel-default-base 6.12.0-160000.39.1.160000.2.25 openSUSE-SU-2026:22091-1
openSUSE Leap 16.0 kernel-rt +11 6.12.0-160000.39.1 openSUSE-SU-2026:22091-1

Azure Linux

ReleasePackageFixed inAdvisory
Azure Linux 3 kernel 6.6.152.1-1 —

Advisories 39

References