CVE-2026-74331

What the bug is

A recursive locking deadlock can occur in the firmware loader's power management notification handler. During system suspend or hibernation preparation, fw_pm_notify() calls device_cache_fw_images(). This function acquires fw_lock to set the firmware cache state to FW_LOADER_START_CACHE and then iterates over all devices using dpm_for_each_dev() while still holding the lock. For each device, dev_cache_fw_image() schedules asynchronous work to cache the firmware. If memory allocation for the async work entry fails (e.g., in out-of-memory conditions), async_schedule_node_domain() falls back to executing the work function synchronously in the current thread. The synchronous execution path (__async_dev_cache_fw_image() -> cache_firmware() -> request_firmware() -> assign_fw()) attempts to acquire fw_lock again. Since the current thread already holds fw_lock, this results in a recursive locking deadlock. Fix this by releasing fw_lock immediately after updating the cache state and before calling dpm_for_each_dev(). The lock is only needed to protect the state update. Concurrent firmware requests will correctly see the FW_LOADER_START_CACHE state and use the piggyback mechanism, which is independently protected by its own fwc->name_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/base/firmware_loader/main.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 -w CONFIG_FW_LOADER /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 builds this code. Every release below compiles the affected file into the kernels it ships.

• bookworm, trixie, forky, sidy

y

built into the kernel image on every flavour - only a patch removes it

Build switch

CONFIG_FW_LOADER

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

2026-08-15 (2 months ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.24%, higher than 13.6% 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
3.7	5.10.261	806cb8fabfde
3.7	5.15.212	7865a1bfd20d
3.7	6.1.178	490b0385e4cf
3.7	6.6.145	38149b57427c
3.7	6.12.97	a5b2a68a391b
3.7	6.18.40	f25d6e4ec4c2
3.7	7.1.5	c0f2dedd41fe
3.7	7.2	d3ec78f8f8d4