In the Linux kernel, the following vulnerability has been resolved:
USB: dummy-hcd: Fix locking/synchronization error
Syzbot testing was able to provoke an addressing exception and crash
in the usb_gadget_udc_reset() routine in
drivers/usb/gadgets/udc/core.c, resulting from the fact that the
routine was called with a second ("driver") argument of NULL. The bad
caller was set_link_state() in dummy_hcd.c, and the problem arose
because of a race between a USB reset and driver unbind.
These sorts of races were not supposed to be possible; commit
7dbd8f4cabd9 ("USB: dummy-hcd: Fix erroneous synchronization change"),
along with a few followup commits, was written specifically to prevent
them. As it turns out, there are (at least) two errors remaining in
the code. Another patch will address the second error; this one is
concerned with the first.
The error responsible for the syzbot crash occurred because the
stop_activity() routine will sometimes drop and then re-acquire the
dum->lock spinlock. A call to stop_activity() occurs in
set_link_state() when handling an emulated USB reset, after the test
of dum->ints_enabled and before the increment of dum->callback_usage.
This allowed another thread (doing a driver unbind) to sneak in and
grab the spinlock, and then clear dum->ints_enabled and dum->driver.
Normally this other thread would have to wait for dum->callback_usage
to go down to 0 before it would clear dum->driver, but in this case it
didn't have to wait since dum->callback_usage had not yet been
incremented.
The fix is to increment dum->callback_usage _before_ calling
stop_activity() instead of after. Then the thread doing the unbind
will not clear dum->driver until after the call to
usb_gadget_udc_reset() safely returns and dum->callback_usage has been
decremented again.
References
Configurations
Configuration 1 (hide)
|
History
15 May 2026, 18:05
| Type | Values Removed | Values Added |
|---|---|---|
| CPE | cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.0:rc7:*:*:*:*:*:* |
|
| CWE | CWE-667 | |
| First Time |
Linux linux Kernel
Linux |
|
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 5.5 |
| References | () https://git.kernel.org/stable/c/218886b2ef2dea7627d3700ab0abaf4bf9d1161f - Patch | |
| References | () https://git.kernel.org/stable/c/616a63ff495df12863692ab3f9f7b84e3fa7a66d - Patch | |
| References | () https://git.kernel.org/stable/c/6350c7dd33ab481ef41c931a238361490c32d15c - Patch | |
| References | () https://git.kernel.org/stable/c/69ab97a693251d6a6093e630060a3c744fd58524 - Patch | |
| References | () https://git.kernel.org/stable/c/791966f85b439b261bf19865cf1c07c065ffb4b4 - Patch | |
| References | () https://git.kernel.org/stable/c/805b1833d6ed6da5086e610578a28e71bb54fbbb - Patch | |
| References | () https://git.kernel.org/stable/c/cc97fb5969177cccce2e23b31298df220fc7570d - Patch | |
| References | () https://git.kernel.org/stable/c/efbd9441f1e769a7aae1813d497cec09cbdff031 - Patch |
08 May 2026, 14:16
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-05-08 14:16
Updated : 2026-05-15 18:05
NVD link : CVE-2026-43327
Mitre link : CVE-2026-43327
CVE.ORG link : CVE-2026-43327
JSON object : View
Products Affected
linux
- linux_kernel
CWE
CWE-667
Improper Locking