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CVE-2026-72488
soundwire: fix bug in sdw_add_element_group_count found by syzkaller
Published 2026-08-15 (2 months ago) by the Linux kernel CNA. Subsystem drivers/soundwire. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-72488 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 | vulnerable | 6.1.190-1 | No fix published anywhere yet, neither in Debian nor upstream for the series bookworm tracks. Watch the Debian tracker page for this CVE. Advisories for bookworm have historically landed a median of 23 days after publication. |
| Debian 13trixie | vulnerable | 6.12.113-1 | No fix published anywhere yet, neither in Debian nor upstream for the series trixie tracks. Watch the Debian tracker page for this CVE. Advisories for trixie have historically landed a median of 11 days after publication. |
| 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
The original implementation caused an out-of-bounds memory access in the sdw_add_element_group_count for-loop when i == num. for (i = 0; i <= num; i++) { if (rate == group->rates[i] && lane == group->lanes[i]) ... To fix this error, the function now checks for existing rate/lane entries in the group(a function parameter) using a for-loop before adding them. No functional changes apart from this fix.
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.
drivers/soundwire/generic_bandwidth_allocation.c
- What this is
- SOUNDWIRE SUBSYSTEMMAINTAINERS section matched on drivers/soundwire/ · linux-sound@vger.kernel.org · Supported
- Kernel module
- soundwire_generic_allocation
Check it on the machine
grep -wE 'CONFIG_SOUNDWIRE|CONFIG_SOUNDWIRE_GENERIC_ALLOCATION' /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 soundwire_generic_allocationPrints 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/cloud-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, s390x/s390x
- forky, sidMnot built on amd64/cloud-amd64, arm64/cloud-arm64, armhf/armmp, armhf/armmp-lpae, loong64/loong64, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, s390x/s390x
- M
- a module where it is built at all; some flavours do not build it
- Build switches
- CONFIG_SOUNDWIRE, CONFIG_SOUNDWIRE_GENERIC_ALLOCATION
- 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
- 0.17%, higher than 5.5% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- drivers/soundwire
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 5.10 | 6.18.40 | a454f61747c9 |
| 5.10 | 7.1.5 | e483a406a23a |
| 5.10 | 7.2 | f772ff5a0e67 |
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
- Vulnerable sdw_add_element_group_count is reached only via local ALSA PCM ioctl (SNDRV_PCM_IOCTL_PREPARE/HW_PARAMS) on /dev/snd/pcmC*D*, through asoc_sdw_prepare -> sdw_prepare_stream -> sdw_compute_params on Intel SoundWire machines; no network or adjacent-network entry point exists.
- AC:LAttack complexity, low
- The off-by-one loop (i <= num when num==group->count) deterministically reads one slot past the rates/lanes arrays whenever a second distinct rate/lane group entry is added, which an attacker can trigger by preparing SoundWire streams that exercise multilane assignment or multiple active bus runtimes without races or external state.
- PR:LPrivileges required, low
- Exploitation requires only the ability to open and ioctl the ALSA PCM character device (typically granted to unprivileged desktop users via the audio group or logind seat ACLs on Intel SOF/SoundWire laptops); no CAP_SYS_ADMIN, real root, or non-namespace capability is checked on this path.
- UI:NUser interaction, none
- The attacker's own process issues the PCM prepare/hw_params ioctls that drive bandwidth recomputation; no separate victim must mount filesystems, open files, or take any other action beyond the attacker already having local device access.
- S:UScope, unchanged
- The out-of-bounds access corrupts/read kernel heap memory within the SoundWire bandwidth allocator in the same kernel security domain; it does not cross VM, container, IOMMU, or sandbox boundaries.
- C:HConfidentiality impact, high
- When i==group->count the loop compares against group->rates[i] and group->lanes[i] one element beyond the allocated arrays, leaking adjacent kmalloc heap contents; per kernel guidance unbounded out-of-bounds reads in the allocator path warrant High confidentiality impact.
- I:HIntegrity impact, high
- Even though the immediate fault is an OOB read, the same loop guards heap-backed dynamic expansion that then writes attacker-influenced rate/lane tuples into rates[]/lanes[]; adjacent-heap corruption from the read plus controlled follow-on writes is leverageable for integrity compromise consistent with similar SoundWire CVE scoring.
- A:HAvailability impact, high
- The out-of-bounds read can fault on unmapped adjacent slab memory or trip KASAN/hardened checks (as syzkaller reported), producing kernel oops/panic and aborting stream prepare, leaving audio/DSP subsystems unavailable on affected Intel SoundWire platforms.