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CVE-2026-46157
ALSA: pcm: oss: Fix data race at accessing runtime.oss.trigger
Published 2026-05-28 (5 months ago) by the Linux kernel CNA. Subsystem sound/core. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-46157 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 | fixed | 6.12.88-1 | Update the kernel and reboot. Fixed in 6.12.88-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.0.7-1 | Update the kernel and reboot. Fixed in 7.0.7-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.0.7-1 | Update the kernel and reboot. Fixed in 7.0.7-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
Currently the runtime.oss.trigger field may be accessed concurrently without protection, which may lead to the data race. And, in this case, it may lead to more severe problem because it's a bit field; as writing the data, it may overwrite other bit fields as well, which confuses the operation completely, as spotted by fuzzing. Fix it by covering runtime.oss.trigger bit fled also with the existing params_lock mutex in both snd_pcm_oss_get_trigger() and snd_pcm_oss_poll().
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/core/oss/pcm_oss.c
- What this is
- SOUNDMAINTAINERS section matched on sound/ · linux-sound@vger.kernel.org · Maintained
- Kernel module
- snd_pcm_oss
Check it on the machine
grep -wE 'CONFIG_SND|CONFIG_SND_OSSEMUL|CONFIG_SND_PCM_OSS' /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_pcm_ossPrints 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.
- bookworm, trixie, forky, sidMnot built on amd64/cloud-amd64, arm64/cloud-arm64
- M
- a module where it is built at all; some flavours do not build it
- Build switches
- CONFIG_SND, CONFIG_SND_OSSEMUL, CONFIG_SND_PCM_OSS
- 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
- 2026-05-28 (5 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
- 0.14%, higher than 2.7% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- sound/core
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 2.6.12 | 6.12.88 | 49f9d048845b |
| 2.6.12 | 6.18.30 | ac3e9b55b7da |
| 2.6.12 | 7.0.7 | 6b01c1bc9a47 |
| 2.6.12 | 7.1 | 901ac0ff15ed |
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 vulnerable code is reached only through the OSS PCM device file (/dev/dsp) via poll() and ioctl(SNDCTL_DSP_GETTRIGGER); there is no network exposure, so local access is required.
- AC:LAttack complexity, low
- This is a data race where the attacker controls both sides—issuing concurrent poll()/select() and trigger ioctls from multiple threads on the same fd—so per guidance the complexity is Low.
- PR:LPrivileges required, low
- Triggering requires opening the OSS audio device, available to an unprivileged local user with audio access (audio group / logind ACL); no real root or capability is needed and the path has no privilege checks.
- UI:NUser interaction, none
- The attacker performs all setup and race triggering itself; no action by another user is required.
- S:UScope, unchanged
- The flaw and its impact remain within the kernel's security authority, with no crossing of a VM, IOMMU, or sandbox boundary.
- C:HConfidentiality impact, high
- Clobbering the params/prepare control bits desynchronizes buffer (re)allocation and preparation, allowing use of a stale/mis-sized runtime->oss.buffer that can leak adjacent kernel heap contents through the OSS read path.
- I:HIntegrity impact, high
- The same bit-field corruption can drive buffer free/realloc and prepare mismanagement, producing a use-after-free/out-of-bounds write primitive on the heap-allocated oss.buffer.
- A:HAvailability impact, high
- The "confused" operation from corrupted control flags readily produces a kernel oops/panic, and the potential UAF on oss.buffer crashes the kernel even when not fully exploited.