CVE-2026-68216: media: pwc: Return queued buffers on start_streaming() failure

From: Greg Kroah-Hartman <[email protected]>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

media: pwc: Return queued buffers on start_streaming() failure

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.

pwc's start_streaming() had two early returns that hit this trap:
-ENODEV when the USB device was already disconnected, and -ERESTARTSYS
when mutex_lock_interruptible() was interrupted by a signal.  Call the
existing pwc_cleanup_queued_bufs() helper with VB2_BUF_STATE_QUEUED
before returning (matching the state already used by the
pwc_isoc_init() error path in the same function).

This mirrors the uvcvideo fix in commit 4cf3b6fd54eb ("media: uvcvideo:
Return queued buffers on start_streaming() failure").

The Linux kernel CVE team has assigned CVE-2026-68216 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 3.5 with commit ceede9fa8939e40ad0ddb4ad1355f45c6f1d3478 and fixed in 6.6.148 with commit f2f9fcacd81953dde6cb86312ab13ca13e689664
	Issue introduced in 3.5 with commit ceede9fa8939e40ad0ddb4ad1355f45c6f1d3478 and fixed in 6.12.101 with commit 5d7cc2634c3843a1414a0f6407aa17f1f91dee60
	Issue introduced in 3.5 with commit ceede9fa8939e40ad0ddb4ad1355f45c6f1d3478 and fixed in 6.18.42 with commit cb16b79a2be2cec9c3ebe4147490817c4d8b1de3
	Issue introduced in 3.5 with commit ceede9fa8939e40ad0ddb4ad1355f45c6f1d3478 and fixed in 7.1.6 with commit a4f8f629983f643333e49df90557805469bcbb25
	Issue introduced in 3.5 with commit ceede9fa8939e40ad0ddb4ad1355f45c6f1d3478 and fixed in 7.2-rc1 with commit 975b2ee20e569d47821e4f6c9761b4664d48a6a4

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-68216
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/media/usb/pwc/pwc-if.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/f2f9fcacd81953dde6cb86312ab13ca13e689664
	https://git.kernel.org/stable/c/5d7cc2634c3843a1414a0f6407aa17f1f91dee60
	https://git.kernel.org/stable/c/cb16b79a2be2cec9c3ebe4147490817c4d8b1de3
	https://git.kernel.org/stable/c/a4f8f629983f643333e49df90557805469bcbb25
	https://git.kernel.org/stable/c/975b2ee20e569d47821e4f6c9761b4664d48a6a4