CVE-2026-68416

What the bug is

When device_register() or mtd_nvmem_add() fails inside add_mtd_device() for a partition, the error handling triggers mtd_release() via put_device() or device_unregister(). mtd_release() calls release_mtd_partition() which frees the mtd_info structure. However, callers such as mtd_add_partition() and add_mtd_partitions() also call free_partition() in their error paths, resulting in a double free. Additionally, release_mtd_partition() hits WARN_ON(!list_empty( &mtd->part.node)) because the partition node is still linked in the parent's partitions list when the release callback fires from the add_mtd_device() error path. Fix this by overriding dev->type and dev->release before put_device() in the error paths, so that device_release() invokes a no-op function instead of mtd_release(). For the mtd_nvmem_add() failure case, device_unregister() is replaced with device_del() to separate the device removal from the final kobject reference drop, allowing the override to take effect before put_device() is called. The callers' error paths (list_del + free_partition) remain the sole owners of mtd_info lifetime on add_mtd_device() failure, which is the expected contract. The normal partition teardown path is not affected: del_mtd_device() goes through kref_put() -> mtd_device_release() -> device_unregister() with dev->type still set to &mtd_devtype, so mtd_release() -> release_mtd_partition() continues to work correctly for the regular removal case.

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/mtd/mtdcore.c

What this is

MEMORY TECHNOLOGY DEVICES (MTD)MAINTAINERS section matched on drivers/mtd/ · linux-mtd@lists.infradead.org · Maintained

Kernel module

mtd

Check it on the machine

grep -w CONFIG_MTD /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 mtd

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.

• bookworm, trixie, forky, sid, bookworm · linux-6.12Bnot built on amd64/cloud-amd64, arm64/cloud-arm64

B

built in on some, a module on others, absent on the rest

Build switch

CONFIG_MTD

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

2026-08-10 (2 months ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.16%, higher than 4.3% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

unimportantsource

Subsystem

drivers/mtd

Upstream fixes

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

Introduced	Fixed in	Commit
6.6	6.6.148	ffe21a3545b4
6.6	6.12.101	e1e96aca1bdf
6.6	6.18.42	f98ae09c727d
6.6	7.1.6	820f983d6419
6.6	7.2	9d4af746af8c

Debian advisories