CVE-2026-74437: media: uvcvideo: Fix deadlock if uvc_status_stop is called from async_ctrl.work

Greg Kroah-Hartman <[email protected]>
Newsgroups org.kernel.vger.linux-cve-announce
Message-ID <2026081516-CVE-2026-74437-cf86@gregkh>
From: Greg Kroah-Hartman <[email protected]>

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

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

media: uvcvideo: Fix deadlock if uvc_status_stop is called from async_ctrl.work

If a UVC camera has an asynchronous control, uvc_status_stop may be
called from async_ctrl.work:

uvc_ctrl_status_event_work()
    uvc_ctrl_status_event()
        uvc_ctrl_clear_handle()
	    uvc_pm_put()
	        uvc_status_put()
		    uvc_status_stop()
		        cancel_work_sync()

This will cause a deadlock, since cancel_work_sync will wait for
uvc_ctrl_status_event_work to complete before returning.

Fix this by returning early from uvc_status_stop if we are currently in
the work function. flush_status now remains false until uvc_status_start
is called again, ensuring that uvc_ctrl_status_event_work won't resubmit
the URB.

The Linux kernel CVE team has assigned CVE-2026-74437 to this issue.


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

	Issue introduced in 6.16 with commit a32d9c41bdb86e09ce731aa5fd3add89ac2103a5 and fixed in 6.18.40 with commit 3659deaf7bf690510899a73906b772740d94342c
	Issue introduced in 6.16 with commit a32d9c41bdb86e09ce731aa5fd3add89ac2103a5 and fixed in 7.1.5 with commit 7f6c5fe1633272c926361b73d83dfc6ae01b1504
	Issue introduced in 6.16 with commit a32d9c41bdb86e09ce731aa5fd3add89ac2103a5 and fixed in 7.2-rc1 with commit 6d27f92c54ce28cfbd2a8a479a96d6f4a781b7d2

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-2026-74437
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/uvc/uvc_status.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/3659deaf7bf690510899a73906b772740d94342c
	https://git.kernel.org/stable/c/7f6c5fe1633272c926361b73d83dfc6ae01b1504
	https://git.kernel.org/stable/c/6d27f92c54ce28cfbd2a8a479a96d6f4a781b7d2
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