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CVE-2026-72304
ASoC: SOF: ipc4-control: Fix TOCTOU in sof_ipc4_bytes_put
Published 2026-08-15 (2 months ago) by the Linux kernel CNA. Subsystem sound/soc. Debian urgency: unimportant.
What to do, per Debian release
Debian's own status for CVE-2026-72304 in every release this site tracks, and what each one means in practice. Every status below is the one the Debian Security Team publishes for this CVE. source
| Release | Status | Version | What this means |
|---|---|---|---|
| Debian 12bookworm | not affected | 6.1.190-1 | Nothing to do. bookworm never shipped the vulnerable code. |
| Debian 13trixie | fixed | 6.12.100-1 | Update the kernel and reboot. Fixed in 6.12.100-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
In sof_ipc4_bytes_put(), the copy size is derived from the old data->size in the buffer rather than the incoming new data's size field from ucontrol. If the new data has a different size, the copy uses the wrong length: it may truncate valid data or copy stale bytes. Fix by validating and using the incoming data's sof_abi_hdr.size from ucontrol before copying.
Where it lives
The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.
sound/soc/sof/ipc4-control.c
- What this is
- SOUND - SOUND OPEN FIRMWARE (SOF) DRIVERSMAINTAINERS section matched on sound/soc/sof/ · sound-open-firmware@alsa-project.org · Supported
- Kernel module
- snd_sof
Check it on the machine
grep -wE 'CONFIG_SND|CONFIG_SND_SOC|CONFIG_SND_SOC_SOF' /boot/config-$(uname -r)Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.
lsmod | grep -w snd_sofPrints a line if that module is loaded right now, and nothing if it is not. One that is not loaded can still be loaded later by anything that needs it.
Show whether Debian builds this, per release
Debian builds this, but not on every flavour. At least one release below builds the code on some of its kernel flavours and not on others, so the answer depends on the architecture and flavour installed.
- bookwormMnot built on amd64/cloud-amd64, arm64/arm64, arm64/cloud-arm64, arm64/rt/arm64, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, ppc64el/powerpc64le
- trixieMnot built on amd64/cloud-amd64, arm64/cloud-arm64, armel/rpi, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, riscv64/riscv64, s390x/s390x
- forky, sidMnot built on amd64/cloud-amd64, arm64/cloud-arm64, armhf/armmp, armhf/armmp-lpae, loong64/loong64, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, riscv64/riscv64, s390x/s390x
- M
- a module where it is built at all; some flavours do not build it
- Build switches
- CONFIG_SND, CONFIG_SND_SOC, CONFIG_SND_SOC_SOF
- Reads as
- all on means the file is compiled; any one off means it is not.
From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages
Signals
- Published
- 2026-08-15 (2 months ago)source
- CVSS
- 7.8 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.16%, higher than 5.2% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- unimportantsource
- Subsystem
- sound/soc
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 6.4 | 6.6.145 | 266f936db83a |
| 6.4 | 6.12.97 | 4cf6a7ebbf87 |
| 6.4 | 6.18.40 | fb4293173db2 |
| 6.4 | 7.1.5 | 038406abde0d |
| 6.4 | 7.2 | 3ad673e7139c |
Why the CNA scored it this way
Quoted from the kernel CNA's own scoring file, word for word. A highlighted metric carries the most severe value CVSS v3.1 defines for it, which is what pushes the score up. source
- AV:LAttack vector, local
- The bug is reached via SNDRV_CTL_IOCTL_ELEM_WRITE on /dev/snd/controlC* through snd_ctl_elem_write_user() -> snd_sof_bytes_put() -> sof_ipc4_bytes_put(); SOF IPC4 bytes controls are a local ALSA ioctl path, not a network-facing service.
- AC:LAttack complexity, low
- An attacker reliably triggers the flaw with two self-controlled ALSA writes: first establish a small cached data->size, then submit a ucontrol whose sof_abi_hdr.size differs; no race against unrelated victim state is required.
- PR:LPrivileges required, low
- Only a local user who can open ALSA control devices on SOF-equipped Intel laptop/desktop audio hardware is required; typical desktop users in the audio group have this access without real root or init-namespace capabilities.
- UI:NUser interaction, none
- No separate victim action is needed; the attacker issues the control-element write ioctls directly to drive the vulnerable copy and subsequent IPC transmission.
- S:UScope, unchanged
- Impact is confined to the host kernel SOF/ALSA audio subsystem on the same machine; heap disclosure, IPC misuse, or firmware parameter corruption does not cross VM, container, or IOMMU boundaries.
- C:HConfidentiality impact, high
- Validating and copying against stale data->size lets attacker-controlled new_hdr->size bypass bounds checks, so sof_ipc4_set_get_bytes_data() and IPC helpers read beyond the kmalloc control buffer, disclosing adjacent kernel heap memory.
- I:HIntegrity impact, high
- The mismatched copy leaves attacker-influenced stale kernel bytes in control buffers and forwards unvalidated sizes to firmware IPC (including sof_ipc4_set_bytes_control_data() memcpy paths), enabling bounded but attacker-directed kernel memory corruption.
- A:HAvailability impact, high
- Inflated unvalidated data->size values drive large memcpy/IPC loops past the allocated control payload, which can provoke KASAN faults, unhandled page faults, kernel oops, or panic on SOF systems.