CVE-2026-64343: USB: ldusb: fix use-after-free on disconnect race

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

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

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

USB: ldusb: fix use-after-free on disconnect race

mutex_unlock() may access the mutex structure after releasing the lock
and therefore cannot be used to manage lifetime of objects directly
(unlike spinlocks and refcounts). [1][2]

Use a kref to release the driver data to avoid use-after-free in
mutex_unlock() when release() races with disconnect().

[1] a51749ab34d9 ("locking/mutex: Document that mutex_unlock() is
                   non-atomic")
[2] 2b9d9e0a9ba0 ("locking/mutex: Clarify that mutex_unlock(), and most
                   other sleeping locks, can still use the lock object
                   after it's unlocked")

The Linux kernel CVE team has assigned CVE-2026-64343 to this issue.


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

	Issue introduced in 2.6.26 with commit ce0d7d3f575fc1ba6a89c3c651e710355590daff and fixed in 5.10.261 with commit fc55923a972e715f9a27187b47d4920709e23d85
	Issue introduced in 2.6.26 with commit ce0d7d3f575fc1ba6a89c3c651e710355590daff and fixed in 5.15.212 with commit e5a9bdce4bfd3e2226b5f3df5fb8385d6935ee69
	Issue introduced in 2.6.26 with commit ce0d7d3f575fc1ba6a89c3c651e710355590daff and fixed in 6.1.178 with commit af59829e67e11ba2511a9f8e4b9111afc7d1f550
	Issue introduced in 2.6.26 with commit ce0d7d3f575fc1ba6a89c3c651e710355590daff and fixed in 6.6.145 with commit 02ca08fff74cf9b0a3c4d2cacde1c6edeeb95bb4
	Issue introduced in 2.6.26 with commit ce0d7d3f575fc1ba6a89c3c651e710355590daff and fixed in 6.12.96 with commit d8f69404e1d671326f86d378b9f5bfbd56490e9d
	Issue introduced in 2.6.26 with commit ce0d7d3f575fc1ba6a89c3c651e710355590daff and fixed in 6.18.39 with commit 2107a4fc8ff1cf1d52f416c1e5cc8e97413a5915
	Issue introduced in 2.6.26 with commit ce0d7d3f575fc1ba6a89c3c651e710355590daff and fixed in 7.1.4 with commit a3e794136ab5e3ad1e7019175a4b837aec86db4b
	Issue introduced in 2.6.26 with commit ce0d7d3f575fc1ba6a89c3c651e710355590daff and fixed in 7.2-rc3 with commit 19bdfc7b3c179331eafa423d87e1336f43bbfeb8

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-2026-64343
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/usb/misc/ldusb.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/fc55923a972e715f9a27187b47d4920709e23d85
	https://git.kernel.org/stable/c/e5a9bdce4bfd3e2226b5f3df5fb8385d6935ee69
	https://git.kernel.org/stable/c/af59829e67e11ba2511a9f8e4b9111afc7d1f550
	https://git.kernel.org/stable/c/02ca08fff74cf9b0a3c4d2cacde1c6edeeb95bb4
	https://git.kernel.org/stable/c/d8f69404e1d671326f86d378b9f5bfbd56490e9d
	https://git.kernel.org/stable/c/2107a4fc8ff1cf1d52f416c1e5cc8e97413a5915
	https://git.kernel.org/stable/c/a3e794136ab5e3ad1e7019175a4b837aec86db4b
	https://git.kernel.org/stable/c/19bdfc7b3c179331eafa423d87e1336f43bbfeb8