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High · 7.5 CVE-2026-98173 EUVD-2026-93101GHSA-7vf5-5xh7-53fm

smb: client: fix use-after-free of iface in cifs_try_adding_channels()

Published Oct 6, 2026 · Updated Oct 30, 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-5.19 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-5.19 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-5.19 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-6.8 Package: linux-intel-5.13 Package: linux-intel-iot-realtime Package: linux-lowlatency 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-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-5.3 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-5.19 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 Platform: Linux Ecosystem: Azure Linux Ecosystem: Debian Ecosystem: Ubuntu

Description

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

smb: client: fix use-after-free of iface in cifs_try_adding_channels()

cifs_try_adding_channels() iterates ses->iface_list with
list_for_each_entry_safe_from(), which captures the next entry
(niface) under iface_lock. The loop body then drops iface_lock for
the whole duration of cifs_ses_add_channel().

A concurrent interface refresh (SMB3_request_interfaces() ->
parse_server_interfaces()) marks all ifaces inactive and removes and
frees any that are not re-advertised via list_del() + kref_put(),
where release_iface() is a bare kfree(). Since niface typically has
no channel holding a reference, the list reference is its last and it
can be freed inside the unlocked window. On continue, the iterator
advance step then dereferences niface->iface_head.next, and the loop
body reads iface->rdma_capable/is_active, both on freed memory.

Fix this by never keeping an unreferenced list pointer across the
unlocked window. Each channel attempt now re-scans the list from the
head under iface_lock, takes a kref on the selected candidate, and
passes only that referenced candidate to cifs_ses_add_channel().
weight_fulfilled still tracks selection progress, so restarting the
scan preserves the original weighted distribution and the
weight_fulfilled-before-kref_put ordering on the failure path.

Add a per-pass attempts cap so a flapping interface refresh cannot
keep the inner loop spinning within a single tries increment.

Affected products

VendorProductAffectedFixed
Linux Linux 5.19 6.1.191

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 7.2.8-1 —
Debian 13 linux 6.12.113-1 —
Debian 12 linux No fix yet —
Debian 12 linux-6.12 6.12.113-1~deb12u1 —
ReleasePackageFixed inAdvisory
Ubuntu Nvidia-BlueField 24.04 LTS linux-bluefield 6.8.0-1036.41 —
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-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 +32 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-aws-6.8 6.8.0-1069.74~22.04.1 USN-9024-1
Ubuntu 22.04 LTS linux-azure +35 No fix yet —
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-6.8 6.8.0-1071.78~22.04.1 USN-9026-1
Ubuntu 22.04 LTS linux-gcp-6.8 6.8.0-1073.81~22.04.1 USN-9024-1
Ubuntu 22.04 LTS linux-hwe-6.8 6.8.0-149.149~22.04.1 USN-9066-1
Ubuntu 22.04 LTS linux-ibm-6.8 6.8.0-1069.70~22.04.1 USN-9024-1
Ubuntu 22.04 LTS linux-lowlatency-hwe-6.8 6.8.0-149.149.1~22.04.1 USN-9024-1
Ubuntu 22.04 LTS linux-oracle-6.8 6.8.0-1067.71~22.04.1 USN-9025-1
Ubuntu 20.04 LTS linux-gke +28 No fix yet —
Show 8 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
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-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-azure-fips No fix yet —
Ubuntu Pro FIPS-preview 22.04 LTS linux-azure-fips No fix yet —
Ubuntu Pro 20.04 LTS linux-azure-5.15 +1 No fix yet —
ReleasePackageFixed inAdvisory
SLES 15 SP7 kernel-64kb +5 6.4.0-150700.53.87.3 SUSE-SU-2026:4935-1
SLES 15 SP7 kernel-default-base 6.4.0-150700.53.87.3.150700.17.49.2 SUSE-SU-2026:4935-1
SLES 15 SP7 kernel-obs-build 6.4.0-150700.53.87.2 SUSE-SU-2026:4935-1
SLES 15 SP7 kernel-syms 6.4.0-150700.53.87.1 SUSE-SU-2026:4935-1
SLES 15 SP6 kernel-64kb +6 6.4.0-150600.23.143.1 SUSE-SU-2026:4934-1
SLES 15 SP6 kernel-default-base 6.4.0-150600.23.143.1.150600.12.66.3 SUSE-SU-2026:4934-1
Show 9 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
SLES for SAP 16.0 kernel-64kb +8 6.12.0-160000.40.1 SUSE-SU-2026:24446-1
SLES for SAP 16.0 kernel-default-base 6.12.0-160000.40.1.160000.2.29 SUSE-SU-2026:24446-1
SLES for SAP 15 SP6 kernel-default-base 6.4.0-150600.23.143.1.150600.12.66.3 SUSE-SU-2026:4934-1
SLES for SAP 15 SP6 kernel-docs +4 6.4.0-150600.23.143.1 SUSE-SU-2026:4934-1
SLES 16.0 kernel-64kb +8 6.12.0-160000.40.1 SUSE-SU-2026:24446-1, SUSE-SU-2026:24437-1
SLES 16.0 kernel-default-base 6.12.0-160000.40.1.160000.2.29 SUSE-SU-2026:24446-1
SLE Micro 6.2 kernel-default-base 6.12.0-160000.40.1.160000.2.29 SUSE-SU-2026:24422-1
SLE Micro 6.2 kernel-rt +5 6.12.0-160000.40.1 SUSE-SU-2026:24422-1, SUSE-SU-2026:24386-1
SLE Micro 6.1 kernel-default-base 6.4.0-159998.54.1.159998.21.39 SUSE-SU-2026:24379-1
SLE Micro 6.1 kernel-rt +4 6.4.0-159998.54.1 SUSE-SU-2026:24553-1, SUSE-SU-2026:24379-1
SLE Micro 6.0 kernel-default-base 6.4.0-159998.54.1.159998.21.40 SUSE-SU-2026:24371-1
SLE Micro 6.0 kernel-rt +4 6.4.0-159998.54.1 SUSE-SU-2026:24473-1, SUSE-SU-2026:24371-1
SLE Live Patching 15 SP7 kernel-default 6.4.0-150700.53.87.3 SUSE-SU-2026:4935-1
SLE Live Patching 15 SP7 kernel-livepatch-SLE15-SP7-RT_Update_22 1-150700.1.3.1 SUSE-SU-2026:4940-1
SLE Live Patching 15 SP7 kernel-livepatch-SLE15-SP7_Update_23 1-150700.15.3.2 SUSE-SU-2026:4935-1
SLE Live Patching 15 SP6 kernel-default 6.4.0-150600.23.143.1 SUSE-SU-2026:4934-1
SLE Live Patching 15 SP6 kernel-livepatch-SLE15-SP6_Update_33 1-150600.13.5.1 SUSE-SU-2026:4934-1
SUSE Real Time Module 15 SP7 kernel-rt +2 6.4.0-150700.7.81.1 SUSE-SU-2026:4940-1
ReleasePackageFixed inAdvisory
openSUSE Tumbleweed kernel-source 7.2.10-1.1 openSUSE-SU-2026:12131-1
openSUSE Leap 16.0 kernel-default-base 6.12.0-160000.40.1.160000.2.29 openSUSE-SU-2026:22167-1
openSUSE Leap 16.0 kernel-rt +11 6.12.0-160000.40.1 openSUSE-SU-2026:22167-1

Amazon Linux

ReleasePackageFixed inAdvisory
Amazon Linux 2023 kernel-livepatch-6.18.54-121.166 +1 1:1.0-0.amzn2023 ALAS2023-2026-3335, ALAS2023-2026-3192
Amazon Linux 2023 perf6.12 +11 1:6.12.113-138.209.amzn2023 ALAS2023-2026-3335
Amazon Linux 2023 perf6.18 +12 1:6.18.54-121.166.amzn2023 ALAS2023-2026-3192

Azure Linux

ReleasePackageFixed inAdvisory
Azure Linux 3 kernel 6.6.161.1-1 —

Oracle Linux

ReleasePackageFixed inAdvisory
Oracle Linux 9 kernel-uek +34 6.12.0-208.112.5.el10uek ELSA-2026-500572

Advisories 30

References