From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-cve-announce@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@kernel.org>
Subject: CVE-2026-89739: usb: dwc3: gadget: Fix use-after-free in dwc3_gadget_free_endpoints due to race condition
Date: Fri, 11 Sep 2026 21:47:08 +0200 [thread overview]
Message-ID: <2026091104-CVE-2026-89739-00b4@gregkh> (raw)
From: Greg Kroah-Hartman <gregkh@kernel.org>
Description
===========
In the Linux kernel, the following vulnerability has been resolved:
usb: dwc3: gadget: Fix use-after-free in dwc3_gadget_free_endpoints due to race condition
In dwc3_gadget_init_endpoint, &dep->nostream_work is bound with
dwc3_nostream_work, and dwc3_gadget_endpoint_stream_event can queue
this delayed work on system_percpu_wq when a DEPEVT_STREAM_NOSTREAM
event is received.
If we remove the gadget, dwc3_gadget_free_endpoints makes cleanup and
the memory allocated for dep with kzalloc() is released by kfree(dep),
while the delayed work mentioned above may still be pending or
running. The sequence of operations that may lead to a UAF bug is as
follows:
CPU0 CPU1
| dwc3_thread_interrupt
| dwc3_endpoint_interrupt
| dwc3_gadget_endpoint_stream_event
| queue_delayed_work(system_percpu_wq,
| &dep->nostream_work)
dwc3_gadget_free_endpoints |
dwc3_free_trb_pool(dep) |
list_del(&dep->endpoint.ep_list) |
dwc3_debugfs_remove_endpoint_dir(dep) |
kfree(dep) |
// dep is freed |
| dwc3_nostream_work
| // use dep (use-after-free)
Fix it by canceling the delayed work before kfree(dep) in
dwc3_gadget_free_endpoints.
The Linux kernel CVE team has assigned CVE-2026-89739 to this issue.
Affected and fixed versions
===========================
Issue introduced in 6.14 with commit dcfe437492e27d54f3ac491aed024da760f5c43c and fixed in 6.18.50 with commit 448e95c0f3eaa8d99f16ccae92ab94545f14413b
Issue introduced in 6.14 with commit dcfe437492e27d54f3ac491aed024da760f5c43c and fixed in 7.2.4 with commit 93e08b13a7a30e4e78556d993720e0bc36231ec7
Issue introduced in 6.14 with commit dcfe437492e27d54f3ac491aed024da760f5c43c and fixed in 7.3-rc1 with commit 9c855832790cd488d87de1885974f4c37cfe7358
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-2026-89739
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/dwc3/gadget.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/448e95c0f3eaa8d99f16ccae92ab94545f14413b
https://git.kernel.org/stable/c/93e08b13a7a30e4e78556d993720e0bc36231ec7
https://git.kernel.org/stable/c/9c855832790cd488d87de1885974f4c37cfe7358
reply other threads:[~2026-09-11 20:06 UTC|newest]
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