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CVE-2026-72446
ALSA: usb-audio: qcom: reject stream disable with no active interface
Published 2026-08-15 (2 months ago) by the Linux kernel CNA. Subsystem sound/usb. Debian urgency: unimportant.
What to do, per Debian release
Debian's own status for CVE-2026-72446 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 | not affected | 6.12.113-1 | Nothing to do. trixie never shipped the vulnerable code. |
| 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
handle_uaudio_stream_req() resolves an interface index with info_idx_from_ifnum(), which returns -EINVAL when no interface matches. The enable branch and the response: cleanup label both guard against a negative index, but the disable branch does not: it forms info = &uadev[pcm_card_num].info[info_idx] and dereferences it. uadev[].info is a pointer allocated only when a stream is first enabled, so a negative info_idx on the disable path is unsafe in two ways: - If the card was never enabled, .info is NULL and &info[-EINVAL] is a wild pointer; reading info->data_ep_pipe faults (kernel oops). - If the card was enabled at least once (.info allocated) and the disable names an interface that does not match, &info[-EINVAL] points before the allocation; info->data_ep_pipe / info->sync_ep_pipe are an out-of-bounds slab read and, when non-zero, an out-of-bounds 4-byte write (both pipe fields are cleared to 0). That is memory corruption, not just a NULL dereference. The request is reachable from unprivileged local userspace over AF_QIPCRTR. Reject a disable request with no resolved interface, matching the guard the enable path already has.
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/usb/qcom/qc_audio_offload.c
- What this is
- SOUNDMAINTAINERS section matched on sound/ · linux-sound@vger.kernel.org · Maintained
Check it on the machine
grep -wE 'CONFIG_SND|CONFIG_SND_USB_AUDIO_QMI' /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 2 releases. The build rule could not be established for 2 releases, so nothing is claimed about those.
- bookworm, trixie?
- forky, sidn
- ?
- not established - no Makefile entry for the affected file
- n
- not enabled on any flavour - this release does not build the code
Where a release above reads "not established", no build rule for the affected file was found in that release's kernel tree. That is a gap in this lookup, not a finding that the code is absent.
- Build switches
- CONFIG_SND, CONFIG_SND_USB_AUDIO_QMI
- 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 5.3% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- unimportantsource
- Subsystem
- sound/usb
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 6.16 | 6.18.40 | 25a867aa5e67 |
| 6.16 | 7.1.5 | a22356d1f731 |
| 6.16 | 7.2 | bdb640be82e6 |
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
- Exploitation requires sending a crafted QMI stream-disable request via the AF_QIPCRTR local socket API into the kernel-registered UAUDIO QMI server; it is not reachable over the network or by plugging in USB alone.
- AC:LAttack complexity, low
- An attacker can deterministically trigger the bug by sending enable=0 with a valid usb_token for a probed USB-audio card when no matching interface exists; no race or attacker-uncontrollable memory layout is required.
- PR:LPrivileges required, low
- AF_QIPCRTR permits unprivileged local userspace to deliver QMI requests to the registered service without root or CAP_NET_ADMIN, and the fix commit explicitly states the path is reachable from unprivileged userspace.
- UI:NUser interaction, none
- Exploitation is a direct programmatic QMI disable request and does not require the victim to mount filesystems, open files, or perform any interactive action at trigger time.
- S:UScope, unchanged
- The flaw corrupts kernel heap memory within the same kernel security authority; it does not by itself cross a VM, IOMMU, or sandbox boundary to another security domain.
- C:HConfidentiality impact, high
- When a card was previously enabled, a failed interface lookup yields a negative index that performs an out-of-bounds slab read of endpoint pipe fields before the allocated intf_info array, enabling kernel memory disclosure.
- I:HIntegrity impact, high
- The same out-of-bounds path can perform up to two conditional 4-byte writes clearing data_ep_pipe and sync_ep_pipe in adjacent slab memory, constituting exploitable kernel heap corruption rather than a benign crash.
- A:HAvailability impact, high
- If the card was never enabled, info is NULL and indexing with -EINVAL dereferences a wild pointer reading data_ep_pipe, causing a kernel oops/panic and complete local denial of service.