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Unscored CVE-2025-39997 EUVD-2025-34576GHSA-xc3r-7j5x-74w4

ALSA: usb-audio: fix race condition to UAF in snd_usbmidi_free

Published Oct 15, 2025 · Updated Oct 15, 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-5.8 Package: linux-aws-6.14 Package: linux-aws-6.2 Package: linux-aws-6.5 Package: linux-azure Package: linux-azure-5.11 Package: linux-azure-5.13 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-6.2 Package: linux-azure-6.5 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-nvidia-6.14 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-6.2 Package: linux-gcp-6.5 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-6.2 Package: linux-hwe-6.5 Package: linux-hwe-edge Package: linux-intel-5.13 Package: linux-intel-iot-realtime 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-nvidia-6.2 Package: linux-nvidia-6.5 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-5.3 Package: linux-oracle-5.8 Package: linux-oracle-6.14 Package: linux-oracle-6.5 Package: linux-raspi Package: linux-raspi-realtime Package: linux-raspi2 Package: linux-realtime Package: linux-realtime-6.14 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-6.5 Package: linux-starfive-5.19 Package: linux-starfive-6.2 Package: linux-starfive-6.5 Platform: Linux Ecosystem: Debian Ecosystem: Ubuntu

Description

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

ALSA: usb-audio: fix race condition to UAF in snd_usbmidi_free

The previous commit 0718a78f6a9f ("ALSA: usb-audio: Kill timer properly at
removal") patched a UAF issue caused by the error timer.

However, because the error timer kill added in this patch occurs after the
endpoint delete, a race condition to UAF still occurs, albeit rarely.

Additionally, since kill-cleanup for urb is also missing, freed memory can
be accessed in interrupt context related to urb, which can cause UAF.

Therefore, to prevent this, error timer and urb must be killed before
freeing the heap memory.

Affected products

VendorProductAffectedFixed
Linux Linux 6.1.167 – < 6.1.175, 6.15.3 – < 6.16, 6.16 6.1.175

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 6.16.11-1 —
Debian 12 linux 6.1.176-1 —
ReleasePackageFixed inAdvisory
Ubuntu 25.10 linux 6.17.0-6.6 —
Ubuntu 25.10 linux-aws +2 6.17.0-1003.3 —
Ubuntu 25.10 linux-azure 6.17.0-1006.6 —
Ubuntu 25.10 linux-azure-fde No fix yet —
Ubuntu 25.10 linux-raspi 6.17.0-1004.4 —
Ubuntu 25.10 linux-realtime 6.17.0-1002.3 —
Ubuntu 25.10 linux-riscv 6.17.0-6.6.1 —
Ubuntu 24.04 LTS linux-riscv +17 No fix yet —
Ubuntu 22.04 LTS linux-riscv +32 No fix yet —
Ubuntu 20.04 LTS linux-gke +28 No fix yet —
Ubuntu 18.04 LTS linux-gcp +14 No fix yet —
Show 2 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu 16.04 LTS linux-hwe-edge No fix yet —
Ubuntu Pro Realtime 24.04 LTS linux-realtime-6.14 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 6.4.0-150600.23.78.1 SUSE-SU-2025:4140-1
SLES 15 SP6 kernel-azure +2 6.4.0-150600.8.55.1 SUSE-SU-2025:4128-1
SLES 15 SP6 kernel-default-base 6.4.0-150600.23.78.1.150600.12.34.2 SUSE-SU-2025:4140-1
SLES 12 SP5 kernel-syms +2 4.12.14-122.280.1 SUSE-SU-2025:4189-1
Show 10 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
SLES for SAP 16.0 kernel-64kb +7 6.12.0-160000.7.1 SUSE-SU-2025:21147-1
SLES for SAP 16.0 kernel-default-base 6.12.0-160000.6.1.160000.2.4 SUSE-SU-2025:21147-1
SLES 16.0 kernel-64kb +7 6.12.0-160000.7.1 SUSE-SU-2025:21180-1, SUSE-SU-2025:21147-1
SLES 16.0 kernel-default-base 6.12.0-160000.6.1.160000.2.4 SUSE-SU-2025:21147-1
SLE Micro 6.2 kernel-default-base 6.12.0-160000.6.1.160000.2.4 SUSE-SU-2025:21080-1
SLE Micro 6.2 kernel-rt +5 6.12.0-160000.7.1 SUSE-SU-2026:20561-1, SUSE-SU-2025:21080-1
SLE Micro 6.1 kernel-default-base 6.4.0-36.1.21.13 SUSE-SU-2025:21056-1
SLE Micro 6.1 kernel-rt +1 6.4.0-38.1 SUSE-SU-2025:21064-1
SLE Micro 6.1 kernel-source +2 6.4.0-36.1 SUSE-SU-2025:21056-1
SLE Micro 6.0 kernel-default-base 6.4.0-36.1.21.13 SUSE-SU-2025:21040-1
SLE Micro 6.0 kernel-rt +1 6.4.0-38.1 SUSE-SU-2025:21052-1
SLE Micro 6.0 kernel-source +2 6.4.0-36.1 SUSE-SU-2025:21040-1
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 6.4.0-150600.23.78.1 SUSE-SU-2025:4140-1
SLE Live Patching 15 SP6 kernel-livepatch-SLE15-SP6-RT_Update_17 1-150600.1.3.1 SUSE-SU-2025:4301-1
SLE Live Patching 15 SP6 kernel-livepatch-SLE15-SP6_Update_17 1-150600.13.5.1 SUSE-SU-2025:4140-1
SLE Live Patching 12 SP5 kernel-default 4.12.14-122.280.1 SUSE-SU-2025:4189-1
SLE Live Patching 12 SP5 kgraft-patch-SLE12-SP5_Update_74 1-8.5.1 SUSE-SU-2025:4189-1
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 6.4.0-150600.10.58.1 SUSE-SU-2025:4301-1
ReleasePackageFixed inAdvisory
openSUSE Tumbleweed kernel-source 6.17.5-1.1 openSUSE-SU-2025:15671-1
openSUSE Tumbleweed kernel-source-longterm 6.18.16-1.1 openSUSE-SU-2026:10301-1
openSUSE Leap 16.0 kernel-default-base 6.12.0-160000.6.1.160000.2.4 openSUSE-SU-2025:20091-1
openSUSE Leap 16.0 kernel-rt +10 6.12.0-160000.7.1 openSUSE-SU-2025:20091-1
openSUSE Leap 15.6 dtb-aarch64 +10 6.4.0-150600.23.78.1 SUSE-SU-2025:4140-1
openSUSE Leap 15.6 kernel-azure +2 6.4.0-150600.8.55.1 SUSE-SU-2025:4128-1
openSUSE Leap 15.6 kernel-default-base 6.4.0-150600.23.78.1.150600.12.34.2 SUSE-SU-2025:4140-1
openSUSE Leap 15.6 kernel-rt +3 6.4.0-150600.10.58.1 SUSE-SU-2025:4301-1

Advisories 23

References