CVE-2026-64376

What the bug is

firmware_upload_register() -> fw_create_instance() -> device_initialize() After fw_create_instance() succeeds, the lifetime of the embedded struct device is expected to be managed through the device core reference counting, since fw_create_instance() has already called device_initialize(). In firmware_upload_register(), if alloc_lookup_fw_priv() fails after fw_create_instance() succeeds, the code reaches free_fw_sysfs and frees fw_sysfs directly instead of releasing the device reference with put_device(). This may leave the reference count of the embedded struct device unbalanced, resulting in a refcount leak. The issue was identified by a static analysis tool I developed and confirmed by manual review. Fix this by using put_device(fw_dev) in the failure path and letting fw_dev_release() handle the final cleanup, instead of freeing the instance directly from the error path.

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/base/firmware_loader/sysfs_upload.c

What this is

FIRMWARE LOADER (request_firmware)MAINTAINERS section matched on drivers/base/firmware_loader/ · driver-core@lists.linux.dev · Maintained

Check it on the machine

grep -wE 'CONFIG_FW_LOADER|CONFIG_FW_UPLOAD' /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.

Show whether Debian builds this, per release

Debian does not build this code in 1 release. It does build it in 4 releases, so the answer depends on which release the machine runs.

• bookwormn
• trixieYnot built on armel/rpi, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, s390x/s390x
• forky, sidYnot built on armhf/armmp, armhf/armmp-lpae, loong64/loong64, s390x/s390x
• bookworm · linux-6.12Ynot built on armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp

n

not enabled on any flavour - this release does not build the code

Y

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

Build switches

CONFIG_FW_LOADER, CONFIG_FW_UPLOAD

Reads as

all on means the file is compiled; any one off means it is not.

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

2026-07-25 (3 months ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.12%, higher than 1.8% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

drivers/base

Upstream fixes

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

Introduced	Fixed in	Commit
5.19	6.1.178	517676ec7dfc
5.19	6.6.145	46d403da376a
5.19	6.12.96	2619b47a0c81
5.19	6.18.39	92f41769e5fd
5.19	7.1.4	15432f19562f
5.19	7.2	896df22ee576

Debian advisories