CVE-2026-80659

What the bug is

vub300_cmndwork_thread() holds cmd_mutex while it sends a command and waits for the command response. If the response wait times out, __vub300_command_response() kills the command URBs and then synchronously resets the USB device through usb_reset_device(). That reset path re-enters the driver through vub300_pre_reset(), which also takes cmd_mutex. The worker therefore tries to acquire the same mutex recursively while it is still holding it from the command path. This issue was found by our static analysis tool and then manually reviewed against the current tree. The grounded PoC kept the real worker and timeout/reset carrier: vub300_cmndwork_thread() __vub300_command_response() usb_lock_device_for_reset() usb_reset_device() vub300_pre_reset() Lockdep reported the same-task recursive acquisition on cmd_mutex: WARNING: possible recursive locking detected ... (&test_vub300.cmd_mutex) ... at: usb_reset_device... [vuln_msv] ... (&test_vub300.cmd_mutex) ... at: vub300_cmndwork_thread+0x12/0x20 [vuln_msv] Workqueue: vub300_cmd_wq vub300_cmndwork_thread [vuln_msv] *** DEADLOCK *** Return a flag from __vub300_command_response() when the timeout path needs a device reset, then perform the reset after vub300_cmndwork_thread() has cleared the in-flight command state and dropped cmd_mutex. The reset is still attempted before mmc_request_done(), preserving the existing request completion ordering while avoiding the recursive lock.

Where it lives

The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.

drivers/mmc/host/vub300.c

What this is

VUB300 USB to SDIO/SD/MMC bridge chipMAINTAINERS section matched on drivers/mmc/host/vub300.c · linux-mmc@vger.kernel.org · Orphan

Kernel module

vub300

Check it on the machine

grep -w CONFIG_MMC_VUB300 /boot/config-$(uname -r)

Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.

lsmod | grep -w vub300

Prints a line if that module is loaded right now, and nothing if it is not. One that is not loaded can still be loaded later by anything that needs it.

Show whether Debian builds this, per release

Debian builds this, but not on every flavour. At least one release below builds the code on some of its kernel flavours and not on others, so the answer depends on the architecture and flavour installed.

• bookwormMnot built on amd64/cloud-amd64, arm64/cloud-arm64
• trixieMnot built on amd64/cloud-amd64, arm64/cloud-arm64, s390x/s390x
• forky, sidMnot built on amd64/cloud-amd64, arm64/cloud-arm64, loong64/loong64, s390x/s390x

M

a module where it is built at all; some flavours do not build it

Build switch

CONFIG_MMC_VUB300

From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages

Signals

Published

2026-08-28 (2 months ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.22%, higher than 11.6% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

drivers/mmc

Upstream fixes

The versions the CNA records as introducing and fixing this, and the commit for each. source

Introduced	Fixed in	Commit
3.0	5.10.261	8672b8bdbd20
3.0	5.15.212	8344611477c9
3.0	6.1.178	2e6b9a394206
3.0	6.6.145	7ee7a77ec2f4
3.0	6.12.97	9f5e04235a0b
3.0	6.18.40	bf9848a22a8e
3.0	7.1.5	c2e1d3392956
3.0	7.2	ee5fb641c4cc