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CVE-2026-64243
ASoC: codecs: simple-mux: Fix enum control bounds check
Published 2026-07-24 (3 months ago) by the Linux kernel CNA. Subsystem sound/soc. Debian urgency: not yet assigned.
Debian does not build this code. The per-release build detail is under "Where it lives" below.
What to do, per Debian release
Debian's own status for CVE-2026-64243 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 | fixed | 6.1.176-1 | Update the kernel and reboot. Fixed in 6.1.176-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixed | 6.12.94-1 | Update the kernel and reboot. Fixed in 6.12.94-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.0.12-1 | Update the kernel and reboot. Fixed in 7.0.12-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.0.12-1 | Update the kernel and reboot. Fixed in 7.0.12-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
simple_mux_control_put() rejects values greater than e->items, but enum control values are zero based. For the two-entry mux used by this driver, valid values are 0 and 1, so value 2 must be rejected as well. Accepting e->items can store an invalid mux state, pass it to the GPIO setter, and pass it on to the DAPM mux update path where it is used as an index into the enum text array. Use the same >= e->items check used by the ASoC enum helpers.
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/codecs/simple-mux.c
- What this is
- SOUND - SOC LAYER / DYNAMIC AUDIO POWER MANAGEMENT (ASoC)MAINTAINERS section matched on sound/soc/ · linux-sound@vger.kernel.org · Supported
- Kernel module
- none to look for. The file would have gone into snd_soc_simple_mux, and Debian does not compile it into that module, so finding snd_soc_simple_mux in lsmod would say nothing about this CVE.
Check it on the machine
grep -wE 'CONFIG_SND|CONFIG_SND_SOC|CONFIG_SND_SOC_SIMPLE_MUX' /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.
Show whether Debian builds this, per release
Debian does not build this code. In 4 releases below, every kernel flavour Debian publishes has the switch off, so the vulnerable file is compiled into no kernel binary Debian ships.
- bookworm, trixie, forky, sidn
- n
- not enabled on any flavour - this release does not build the code
- Build switches
- CONFIG_SND, CONFIG_SND_SOC, CONFIG_SND_SOC_SIMPLE_MUX
- 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
- 2026-07-24 (3 months ago)source
- CVSS
- 7.1 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.12%, higher than 1.6% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- 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 |
|---|---|---|
| 5.11 | 5.15.210 | 6fb653b62f16 |
| 5.11 | 6.1.176 | d8cc3e747b00 |
| 5.11 | 6.6.143 | 5fe860af8630 |
| 5.11 | 6.12.93 | 2ff3ac6f7664 |
| 5.11 | 6.18.35 | 164dcbec9632 |
| 5.11 | 7.0.12 | 05ef77f02607 |
| 5.11 | 7.1 | f63ad68e18d7 |
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
- An attacker reaches the flaw through SNDRV_CTL_IOCTL_ELEM_WRITE on the local ALSA control device; no network or physical-input path invokes this callback.
- AC:LAttack complexity, low
- Supplying the single invalid enum value 2 directly triggers the vulnerable path on an affected non-hardened build, without a race or conditions outside the attacker’s control.
- PR:LPrivileges required, low
- The ioctl requires ordinary access to /dev/snd/controlC*, commonly granted to the active local user or audio group, and the kernel path performs no capability or namespace checks.
- UI:NUser interaction, none
- After obtaining control-device access, the attacker can issue the ioctl directly without any action by another user.
- S:UScope, unchanged
- The vulnerable ALSA driver and the resulting kernel impacts remain within the host kernel’s security authority and do not cross a virtualization or IOMMU boundary.
- C:HConfidentiality impact, high
- The invalid index performs an out-of-bounds pointer read and then dereferences that pointer through strcmp(); following the required conservative treatment of kernel out-of-bounds reads, confidentiality is scored High.
- I:NIntegrity impact, none
- There is no out-of-bounds write or attacker-controlled write primitive; value 2 is stored in-bounds and the GPIO layer normalizes it to the same Boolean state as valid value 1.
- A:HAvailability impact, high
- The out-of-bounds text pointer commonly resolves to NULL or another invalid address and is dereferenced by strcmp(), causing a kernel oops and potentially a full panic on panic-on-oops systems.