CVE-2026-93049

What the bug is

In mtdswap_add_mtd(), debugfs setup failure after successful blktrans registration can free mbd_dev twice. add_mtd_blktrans_dev() initializes the blktrans device reference and publishes the disk. Once that succeeds, del_mtd_blktrans_dev() tears the disk down and drops the blktrans reference; when that reference reaches zero, blktrans_dev_release() frees the mtd_blktrans_dev. The debugfs failure path called del_mtd_blktrans_dev(mbd_dev), then fell through the common cleanup label and called kfree(mbd_dev) again. Clear the local pointer after deregistration so the common cleanup can still release the mtdswap state without freeing the blktrans object twice. This issue was found by a static analysis checker and confirmed by manual source review.

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/mtdswap.c

What this is

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

Kernel module

mtdswap

Check it on the machine

grep -wE 'CONFIG_MTD|CONFIG_MTD_SWAP' /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 mtdswap

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-6.12Mnot built on amd64/cloud-amd64, arm64/cloud-arm64

M

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

Build switches

CONFIG_MTD, CONFIG_MTD_SWAP

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

2026-09-17 (31 days ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.21%, higher than 10.5% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

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
4.14	5.10.270	ecadb9137aea
4.14	5.15.221	eec130fc9ffb
4.14	6.1.188	d5086911d532
4.14	6.6.157	0ce48c6ddea1
4.14	6.12.110	a82d93fcfdfd
4.14	6.18.52	5c349c533e72
4.14	7.2.6	37be7bc2c2d0
4.14	7.3	779aa4c66a96

Debian advisories