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High · 7.3 CVE-2025-38687 EUVD-2025-26782GHSA-gmr8-hqwc-6phj

comedi: fix race between polling and detaching

Published Sep 4, 2025 · Updated Aug 5, 2026 · Assigned by Linux

Vendor: Linux Product: Linux Package: kernel 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-5.15 Package: linux-aws-5.19 Package: linux-aws-5.3 Package: linux-aws-5.4 Package: linux-aws-5.8 Package: linux-aws-6.14 Package: linux-aws-6.2 Package: linux-aws-6.5 Package: linux-aws-6.8 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-5.15 Package: linux-azure-5.19 Package: linux-azure-5.3 Package: linux-azure-5.4 Package: linux-azure-5.8 Package: linux-azure-6.11 Package: linux-azure-6.14 Package: linux-azure-6.2 Package: linux-azure-6.5 Package: linux-azure-6.8 Package: linux-azure-edge Package: linux-azure-fde Package: linux-azure-fde-5.19 Package: linux-azure-fde-6.14 Package: linux-azure-fde-6.2 Package: linux-azure-fde-6.8 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-4.15 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-5.4 Package: linux-gcp-5.8 Package: linux-gcp-6.11 Package: linux-gcp-6.14 Package: linux-gcp-6.2 Package: linux-gcp-6.5 Package: linux-gcp-6.8 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-5.4 Package: linux-hwe-5.8 Package: linux-hwe-6.11 Package: linux-hwe-6.14 Package: linux-hwe-6.2 Package: linux-hwe-6.5 Package: linux-hwe-6.8 Package: linux-hwe-edge Package: linux-ibm Package: linux-ibm-5.15 Package: linux-ibm-5.4 Package: linux-ibm-6.8 Package: linux-intel Package: linux-intel-5.13 Package: linux-intel-iot-realtime Package: linux-intel-iotg Package: linux-intel-iotg-5.15 Package: linux-iot 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-lts-xenial Package: linux-nvidia Package: linux-nvidia-6.11 Package: linux-nvidia-6.2 Package: linux-nvidia-6.5 Package: linux-nvidia-6.8 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-6.5 Package: linux-oem-6.8 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-5.4 Package: linux-oracle-5.8 Package: linux-oracle-6.14 Package: linux-oracle-6.5 Package: linux-oracle-6.8 Package: linux-raspi Package: linux-raspi-5.4 Package: linux-raspi-realtime Package: linux-raspi2 Package: linux-realtime Package: linux-realtime-6.14 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-6.5 Package: linux-riscv-6.8 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:

comedi: fix race between polling and detaching

syzbot reports a use-after-free in comedi in the below link, which is
due to comedi gladly removing the allocated async area even though poll
requests are still active on the wait_queue_head inside of it. This can
cause a use-after-free when the poll entries are later triggered or
removed, as the memory for the wait_queue_head has been freed. We need
to check there are no tasks queued on any of the subdevices' wait queues
before allowing the device to be detached by the `COMEDI_DEVCONFIG`
ioctl.

Tasks will read-lock `dev->attach_lock` before adding themselves to the
subdevice wait queue, so fix the problem in the `COMEDI_DEVCONFIG` ioctl
handler by write-locking `dev->attach_lock` before checking that all of
the subdevices are safe to be deleted. This includes testing for any
sleepers on the subdevices' wait queues. It remains locked until the
device has been detached. This requires the `comedi_device_detach()`
function to be refactored slightly, moving the bulk of it into new
function `comedi_device_detach_locked()`.

Note that the refactor of `comedi_device_detach()` results in
`comedi_device_cancel_all()` now being called while `dev->attach_lock`
is write-locked, which wasn't the case previously, but that does not
matter.

Thanks to Jens Axboe for diagnosing the problem and co-developing this
patch.

Affected products

VendorProductAffectedFixed
Linux Linux 3.14 5.4.297

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 6.16.3-1 —
Debian 13 linux 6.12.43-1 —
Debian 12 linux 6.1.153-1 DSA-6009-1
Debian 11 linux 5.10.244-1 DLA-4327-1
Debian 11 linux-6.1 6.1.153-1~deb11u1 DLA-4328-1
ReleasePackageFixed inAdvisory
Ubuntu Nvidia-BlueField 24.04 LTS linux-bluefield 6.8.0-1016.20 —
Ubuntu Nvidia-BlueField 22.04 LTS linux-bluefield 5.15.0-1081.83 —
Ubuntu 25.10 linux-azure-fde No fix yet —
Ubuntu 24.04 LTS linux 6.8.0-100.100 USN-8028-1
Ubuntu 24.04 LTS linux-aws +1 6.8.0-1046.49 USN-8028-5
Ubuntu 24.04 LTS linux-azure 6.8.0-1046.52 USN-8074-1
Ubuntu 24.04 LTS linux-azure-fde 6.8.0-1046.53 —
Ubuntu 24.04 LTS linux-azure-nvidia 6.8.0-1039.42 —
Ubuntu 24.04 LTS linux-gcp 6.8.0-1047.50 USN-8031-3
Ubuntu 24.04 LTS linux-gke 6.8.0-1043.48 USN-8031-3
Ubuntu 24.04 LTS linux-gkeop 6.8.0-1030.33 USN-8028-5
Ubuntu 24.04 LTS linux-ibm 6.8.0-1044.44 USN-8028-8
Ubuntu 24.04 LTS linux-intel +19 No fix yet —
Ubuntu 24.04 LTS linux-lowlatency 6.8.0-100.100.1 USN-8052-1
Ubuntu 24.04 LTS linux-nvidia-lowlatency 6.8.0-1046.49.1 USN-8028-7
Ubuntu 24.04 LTS linux-nvidia-tegra 6.8.0-1020.20 —
Ubuntu 24.04 LTS linux-oracle 6.8.0-1043.44 USN-8028-5
Ubuntu 24.04 LTS linux-raspi 6.8.0-1047.51 USN-8028-1
Ubuntu 24.04 LTS linux-xilinx 6.8.0-1023.24 USN-8052-2
Ubuntu 22.04 LTS linux +1 5.15.0-163.173 USN-7909-1
Ubuntu 22.04 LTS linux-aws 5.15.0-1097.104 USN-7909-1
Ubuntu 22.04 LTS linux-aws-6.8 +1 6.8.0-1046.49~22.04.1 USN-8028-5
Ubuntu 22.04 LTS linux-azure 5.15.0-1101.110 USN-7910-2
Ubuntu 22.04 LTS linux-azure-6.8 6.8.0-1051.57~22.04.1 USN-8126-1
Ubuntu 22.04 LTS linux-azure-fde 5.15.0-1102.111.1 —
Ubuntu 22.04 LTS linux-azure-fde-6.8 6.8.0-1046.53~22.04.1 —
Ubuntu 22.04 LTS linux-gcp 5.15.0-1097.106 USN-7909-4
Ubuntu 22.04 LTS linux-gcp-6.8 6.8.0-1047.50~22.04.2 USN-8031-1
Ubuntu 22.04 LTS linux-gke 5.15.0-1093.99 USN-7909-4
Ubuntu 22.04 LTS linux-gkeop 5.15.0-1080.88 USN-7909-4
Ubuntu 22.04 LTS linux-hwe-6.8 +1 6.8.0-100.100~22.04.1 USN-8028-6
Ubuntu 22.04 LTS linux-ibm +1 5.15.0-1091.94 USN-7909-5, USN-7909-1
Ubuntu 22.04 LTS linux-ibm-6.8 6.8.0-1044.44~22.04.1 USN-8028-8
Ubuntu 22.04 LTS linux-intel-iotg 5.15.0-1092.98 USN-7909-1
Ubuntu 22.04 LTS linux-kvm 5.15.0-1089.94 USN-7933-1
Ubuntu 22.04 LTS linux-lowlatency-hwe-6.8 6.8.0-100.100.1~22.04.1 USN-8028-6
Ubuntu 22.04 LTS linux-nvidia 5.15.0-1092.93 USN-7909-1
Ubuntu 22.04 LTS linux-nvidia-tegra 5.15.0-1049.49 USN-7909-1
Ubuntu 22.04 LTS linux-nvidia-tegra-igx 5.15.0-1038.38 USN-7909-1
Ubuntu 22.04 LTS linux-oracle 5.15.0-1094.100 USN-7909-1
Ubuntu 22.04 LTS linux-oracle-6.8 6.8.0-1043.44~22.04.1 USN-8028-5
Ubuntu 22.04 LTS linux-riscv +32 No fix yet —
Ubuntu 22.04 LTS linux-xilinx-zynqmp 5.15.0-1061.65 USN-7909-1
Show 18 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 6.8.0-2037.38 USN-8028-3
Ubuntu Pro Realtime 24.04 LTS linux-realtime 6.8.1-1041.42 USN-8028-3
Ubuntu Pro Realtime 24.04 LTS linux-realtime-6.14 No fix yet —
Ubuntu Pro Realtime 22.04 LTS linux-intel-iot-realtime 5.15.0-1089.91 USN-7909-2
Ubuntu Pro Realtime 22.04 LTS linux-realtime 5.15.0-1096.105 USN-7909-2
Ubuntu Pro Realtime 22.04 LTS linux-realtime-6.8 6.8.1-1041.42~22.04.1 USN-8028-2
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 6.8.0-1046.49+fips1 USN-8028-4
Ubuntu Pro FIPS-updates 24.04 LTS linux-azure-fips 6.8.0-1046.52+fips1 USN-8074-2
Ubuntu Pro FIPS-updates 24.04 LTS linux-fips 6.8.0-100.100+fips1 USN-8028-4
Ubuntu Pro FIPS-updates 24.04 LTS linux-gcp-fips 6.8.0-1047.50+fips1 USN-8031-2
Ubuntu Pro FIPS-updates 22.04 LTS linux-aws-fips 5.15.0-1097.104+fips1 USN-7909-3
Ubuntu Pro FIPS-updates 22.04 LTS linux-azure-fips 5.15.0-1101.110+fips1 USN-7910-1
Ubuntu Pro FIPS-updates 22.04 LTS linux-fips 5.15.0-163.173+fips1 USN-7909-3
Ubuntu Pro FIPS-updates 22.04 LTS linux-gcp-fips 5.15.0-1097.106+fips1 USN-7909-3
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 5.15.0-1097.104~20.04.1 USN-7909-1
Ubuntu Pro 20.04 LTS linux-azure-5.15 5.15.0-1102.111~20.04.1 USN-7938-1
Ubuntu Pro 20.04 LTS linux-gcp-5.15 5.15.0-1097.106~20.04.1 USN-7909-1
Ubuntu Pro 20.04 LTS linux-hwe-5.15 +1 5.15.0-163.173~20.04.1 USN-7909-1
Ubuntu Pro 20.04 LTS linux-ibm-5.15 5.15.0-1091.94~20.04.1 USN-7909-1
Ubuntu Pro 20.04 LTS linux-intel-iotg-5.15 5.15.0-1092.98~20.04.1 USN-7909-1
Ubuntu Pro 20.04 LTS linux-nvidia-tegra-5.15 5.15.0-1049.49~20.04.1 USN-7909-1
Ubuntu Pro 20.04 LTS linux-oracle-5.15 5.15.0-1094.100~20.04.1 USN-7909-1
Ubuntu Pro 20.04 LTS linux-riscv-5.15 5.15.0-1092.96~20.04.1 —
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 —
ReleasePackageFixed inAdvisory
SLES 15 SP7 kernel-64kb +6 6.4.0-150700.53.22.1 SUSE-SU-2025:4057-1
SLES 15 SP7 kernel-azure +2 6.4.0-150700.20.18.1 SUSE-SU-2025:4132-1
SLES 15 SP7 kernel-default-base 6.4.0-150700.53.22.1.150700.17.15.1 SUSE-SU-2025:4057-1
SLES 15 SP6 kernel-64kb +6 6.4.0-150600.23.73.1 SUSE-SU-2025:03600-1
SLES 15 SP6 kernel-azure +2 6.4.0-150600.8.52.1 SUSE-SU-2025:03634-1
SLES 15 SP6 kernel-default-base 6.4.0-150600.23.73.1.150600.12.32.1 SUSE-SU-2025:03600-1
Show 9 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
SLES for SAP 16.0 kernel-64kb +7 6.12.0-160000.6.1 SUSE-SU-2025:21139-1
SLES for SAP 16.0 kernel-default-base 6.12.0-160000.6.1.160000.2.4 SUSE-SU-2025:21139-1
SLES 16.0 kernel-64kb +7 6.12.0-160000.6.1 SUSE-SU-2025:21179-1, SUSE-SU-2025:21139-1
SLES 16.0 kernel-default-base 6.12.0-160000.6.1.160000.2.4 SUSE-SU-2025:21139-1
SLE Micro 6.2 kernel-default-base 6.12.0-160000.6.1.160000.2.4 SUSE-SU-2025:21074-1
SLE Micro 6.2 kernel-rt +5 6.12.0-160000.6.1 SUSE-SU-2026:20560-1, SUSE-SU-2025:21074-1
SLE Micro 6.1 kernel-default-base 6.4.0-35.1.21.12 SUSE-SU-2025:20861-1
SLE Micro 6.1 kernel-rt +1 6.4.0-37.1 SUSE-SU-2025:20898-1
SLE Micro 6.1 kernel-source +2 6.4.0-35.1 SUSE-SU-2025:20861-1
SLE Micro 6.0 kernel-default-base 6.4.0-35.1.21.12 SUSE-SU-2025:20851-1
SLE Micro 6.0 kernel-rt +1 6.4.0-37.1 SUSE-SU-2025:20870-1
SLE Micro 6.0 kernel-source +2 6.4.0-35.1 SUSE-SU-2025:20851-1
SLE Live Patching 15 SP7 kernel-default 6.4.0-150700.53.22.1 SUSE-SU-2025:4057-1
SLE Live Patching 15 SP7 kernel-livepatch-SLE15-SP7-RT_Update_6 1-150700.1.3.1 SUSE-SU-2025:4141-1
SLE Live Patching 15 SP7 kernel-livepatch-SLE15-SP7_Update_6 1-150700.15.3.1 SUSE-SU-2025:4057-1
SLE Live Patching 15 SP6 kernel-default 6.4.0-150600.23.73.1 SUSE-SU-2025:03600-1
SLE Live Patching 15 SP6 kernel-livepatch-SLE15-SP6-RT_Update_16 1-150600.1.3.1 SUSE-SU-2025:3751-1
SLE Live Patching 15 SP6 kernel-livepatch-SLE15-SP6_Update_16 1-150600.13.3.1 SUSE-SU-2025:03600-1
SUSE Real Time Module 15 SP7 kernel-rt +2 6.4.0-150700.7.22.1 SUSE-SU-2025:4141-1
SUSE Real Time Module 15 SP6 kernel-rt +3 6.4.0-150600.10.55.1 SUSE-SU-2025:3751-1
ReleasePackageFixed inAdvisory
openSUSE Leap 16.0 kernel-default-base 6.12.0-160000.6.1.160000.2.4 openSUSE-SU-2025:20081-1
openSUSE Leap 16.0 kernel-rt +10 6.12.0-160000.6.1 openSUSE-SU-2025:20081-1
openSUSE Leap 15.6 dtb-aarch64 +10 6.4.0-150600.23.73.1 SUSE-SU-2025:03600-1
openSUSE Leap 15.6 kernel-azure +2 6.4.0-150600.8.52.1 SUSE-SU-2025:03634-1
openSUSE Leap 15.6 kernel-default-base 6.4.0-150600.23.73.1.150600.12.32.1 SUSE-SU-2025:03600-1
openSUSE Leap 15.6 kernel-rt +3 6.4.0-150600.10.55.1 SUSE-SU-2025:3751-1

Azure Linux

ReleasePackageFixed inAdvisory
Azure Linux 3 kernel 6.6.104.2-1 —

Oracle Linux

ReleasePackageFixed inAdvisory
Oracle Linux 7 kernel-uek +6 5.4.17-2136.348.3.el8uek ELSA-2025-20663
Oracle Linux 7 kernel-uek-tools 5.4.17-2136.348.3.el7uek ELSA-2025-20663

Advisories 48

References