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CVE-2026-68222
media: msi2500: Return queued buffers on start_streaming() failure
Published 2026-08-10 (2 months ago) by the Linux kernel CNA. Subsystem drivers/media. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-68222 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-4777-1 · 2026-09-08 · text | 6.1.187-1 | Update the kernel and reboot. DLA-4777-1 shipped the fix on 2026-09-08, in 6.1.187-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixed | 6.12.101-1 | Update the kernel and reboot. Fixed in 6.12.101-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.1.6-1 | Update the kernel and reboot. Fixed in 7.1.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.6-1 | Update the kernel and reboot. Fixed in 7.1.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4745-1 · 2026-08-18 · text | 6.12.101-1~deb12u1 | Update the kernel and reboot. DLA-4745-1 shipped the fix on 2026-08-18, in 6.12.101-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
The vb2 framework hands buffers to the driver via buf_queue() before calling start_streaming(). If start_streaming() returns an error without first returning those buffers via vb2_buffer_done(), vb2_start_streaming() fires WARN_ON(owned_by_drv_count) and the queued buffers leak. msi2500_start_streaming() had five error paths that all hit this trap and were further tangled by ret-overwriting between calls: - -ENODEV when the USB device was already disconnected - -ERESTARTSYS when mutex_lock_interruptible() was interrupted - msi2500_set_usb_adc() failure: ret was silently overwritten by the next call (msi2500_isoc_init), so the error was lost entirely - msi2500_isoc_init() failure: cleanup_queued_bufs was called, but the function then fell through to msi2500_ctrl_msg() and again masked the original error by overwriting ret - msi2500_ctrl_msg(CMD_START_STREAMING) failure: no cleanup at all, leaving isoc URBs submitted with no way for the driver to consume them Consolidate the error paths into a small goto chain. Every failure now stops the function, drains the queued-buffer list, and returns the real error code. The ctrl_msg failure path also rolls back the preceding msi2500_isoc_init() via msi2500_isoc_cleanup() before unlocking and draining. The cleanup helper takes a vb2_buffer_state argument so that the start_streaming error paths can pass VB2_BUF_STATE_QUEUED (as expected by userspace on start_streaming failure) while stop_streaming keeps its existing VB2_BUF_STATE_ERROR semantics. This mirrors the uvcvideo fix in commit 4cf3b6fd54eb ("media: uvcvideo: Return queued buffers on start_streaming() failure").
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/media/usb/msi2500/msi2500.c
- What this is
- MSI2500 MEDIA DRIVERMAINTAINERS section matched on drivers/media/usb/msi2500/ · linux-media@vger.kernel.org · Orphan
- Kernel module
- msi2500
Check it on the machine
grep -w CONFIG_USB_MSI2500 /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 msi2500Prints 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, sid, 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 switch
- CONFIG_USB_MSI2500
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
- 2026-08-10 (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
- 0.14%, higher than 2.9% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- drivers/media
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 3.12 | 5.10.265 | c74b680704ba |
| 3.12 | 5.15.216 | 2d10eedb786a |
| 3.12 | 6.1.183 | 2de14ddb4fea |
| 3.12 | 6.6.148 | 1d58229b330b |
| 3.12 | 6.12.101 | bab9d5a67d4d |
| 3.12 | 6.18.42 | 264b5380c4f8 |
| 3.12 | 7.1.6 | 3673cb0a5711 |
| 3.12 | 7.2 | 7201c17786a4 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4777-1 | 2026-09-08 | bookworm 6.1.187-1 | tracker |
| DLA-4745-1 | 2026-08-18 | bookworm 6.12.101-1~deb12u1 | 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 vulnerable code is reached only through a local VIDIOC_STREAMON ioctl on the msi2500 SDR character device /dev/swradioN; no network or remote input is involved, and the failure paths are driven from a local process's syscalls.
- AC:LAttack complexity, low
- The attacker controls both sides of the trigger: hold dev->v4l2_lock from a second thread and send a signal to the STREAMON thread so mutex_lock_interruptible() returns -ERESTARTSYS, hitting the leaking error path deterministically and repeatably.
- PR:LPrivileges required, low
- Only an unprivileged local user with access to the V4L2/SDR device node is needed; on desktop, Android and embedded systems these nodes are granted to the logged-in seat or a device group, and no capability check guards STREAMON.
- UI:NUser interaction, none
- The whole sequence (REQBUFS, QBUF, STREAMON, signal, repeat) is performed by the attacker's own process; no victim action such as plugging in hardware or opening a file is required.
- S:UScope, unchanged
- The corruption is confined to kernel memory managed by the same kernel security authority; no VM, IOMMU or sandbox boundary is crossed.
- C:HConfidentiality impact, high
- Buffers left on dev->queued_bufs after the vb2 core reclaims and later frees them become dangling pointers reused by cleanup_queued_bufs()/get_next_fill_buf(), giving a use-after-free that can be groomed to read reclaimed kernel heap contents back into userspace buffers.
- I:HIntegrity impact, high
- The stale list entries permit list_add_tail() on an already-linked node (list corruption) and vb2_buffer_done()/isoc-handler writes into freed objects, yielding attacker-influenced kernel heap writes exploitable for control-flow hijacking.
- A:HAvailability impact, high
- At minimum the missing buffer return trips WARN_ON(owned_by_drv_count) (fatal with panic_on_warn) and leaks buffers; the resulting list corruption and use-after-free reliably oops or hang the kernel.