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CVE-2026-80967
ALSA: pcxhr: initialize mutexes before requesting threaded IRQ
Published 2026-09-11 (37 days ago) by the Linux kernel CNA. Subsystem sound/pci. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-80967 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 | fixedDLA-4841-1 · 2026-10-17 · text | 6.1.190-1 | Update the kernel and reboot. DLA-4841-1 shipped the fix on 2026-10-17, in 6.1.190-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixedDSA-6528-1 · 2026-09-29 · text | 6.12.111-1 | Update the kernel and reboot. DSA-6528-1 shipped the fix on 2026-09-29, in 6.12.111-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.2.6-1 | Update the kernel and reboot. Fixed in 7.2.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.2.6-1 | Update the kernel and reboot. Fixed in 7.2.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4817-1 · 2026-10-04 · text | 6.12.111-1~deb12u1 | Update the kernel and reboot. DLA-4817-1 shipped the fix on 2026-10-04, in 6.12.111-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
pcxhr_probe() requests pcxhr_threaded_irq() before initializing mgr->lock, even though the threaded handler takes that mutex. Initialize the manager locks before request_threaded_irq() so an early interrupt cannot run against uninitialized mutex state during probe.
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/pci/pcxhr/pcxhr.c
- What this is
- SOUNDMAINTAINERS section matched on sound/ · linux-sound@vger.kernel.org · Maintained
- Kernel module
- snd_pcxhr
Check it on the machine
grep -wE 'CONFIG_SND|CONFIG_SND_PCXHR' /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_pcxhrPrints 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
- trixieMnot built on amd64/cloud-amd64, arm64/cloud-arm64, armel/rpi, s390x/s390x
- forky, sidMnot built on amd64/cloud-amd64, arm64/cloud-arm64, s390x/s390x
- bookworm · linux-6.12Mnot 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_PCXHR
- 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
- 2026-09-11 (37 days ago)source
- CVSS
- 8.4 high
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.18%, higher than 7.6% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- sound/pci
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 3.18 | 5.15.221 | 039602d6ddb1 |
| 3.18 | 6.1.188 | a5f405adb022 |
| 3.18 | 6.6.157 | ede25b7fea0d |
| 3.18 | 6.12.109 | c069b3cfd753 |
| 3.18 | 6.18.50 | 7ef9ad82d95d |
| 3.18 | 7.2.4 | 7cf280fbef5d |
| 3.18 | 7.3 | 6c97817e2059 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4841-1 | 2026-10-17 | bookworm 6.1.190-1 | tracker |
| DLA-4817-1 | 2026-10-04 | bookworm 6.12.111-1~deb12u1 | tracker |
| DSA-6528-1 | 2026-09-29 | trixie 6.12.111-1 | tracker |
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 flaw is reached only from snd-pcxhr PCI probe (pcxhr_probe() -> request_threaded_irq() -> pcxhr_threaded_irq()) on a locally attached Digigram PCXHR board; studio, broadcast, and embedded audio systems enumerate that card at boot or udev bind, which is a local PCI probe path, not a network or USB protocol path.
- AC:LAttack complexity, low
- pcxhr_probe() never masks PLX doorbell IRQs before request_threaded_irq(), so leftover or device-asserted PCXHR_IRQCS_ACTIVE_PCIDB plus TIMER/MASK bits wake pcxhr_threaded_irq() immediately; on preemptible kernels that handler preempts probe before mutex_init(), so the attacker does not depend on an uncontrollable race.
- PR:NPrivileges required, none
- pcxhr_probe() performs no capability or authentication checks; when matching PCI hardware is present, kernel enumeration/udev runs the vulnerable request_threaded_irq() sequence automatically without an OS account or user-namespace privilege.
- UI:NUser interaction, none
- The uninitialized mutex is taken in the threaded IRQ during automatic PCI probe; no victim must open ALSA device nodes, load firmware, or otherwise interact.
- S:UScope, unchanged
- Uninitialized-mutex use and the follow-on NULL mgr->prmh dereference occur inside the host kernel pcxhr driver and do not cross a VM, container, or IOMMU security boundary.
- C:HConfidentiality impact, high
- pcxhr_threaded_irq() takes uninitialized mgr->lock (and pcxhr_msg_thread() may take uninitialized mgr->msg_lock) with a zeroed wait_list, then reads through NULL mgr->prmh; that uninitialized-lock/IRQ-thread memory-safety failure can disclose kernel memory rather than a small bounded leak.
- I:HIntegrity impact, high
- Probe can mutex_init() mgr->lock while the IRQ thread still holds the zeroed mutex, and pcxhr_init_rmh() writes through NULL prmh; that lock-state corruption and invalid kernel write are exploitable memory-corruption/control-flow primitives, not a pure crash.
- A:HAvailability impact, high
- Locking an uninitialized mutex, DEBUG_MUTEXES checks, and NULL dereference of mgr->prmh in pcxhr_msg_thread() cause a kernel oops or panic during probe, fully denying availability.