CVE-2026-72155

What the bug is

In the case of the first block being locked (or the few first blocks), if the user want to fully unlock the device it has two possibilities: - either it asks to unlock the entire device, and this works; - or it asks to unlock just the block(s) that are currently locked, which fails. It fails because the conditions "can_be_top" and "can_be_bottom" are true. Indeed, in this case, we unlock everything, so the TB bit does not matter. However in the current implementation, use_top would be true (as this is the favourite option) and lock_len, which in practice should be reduced down to 0, is set to "nor->params->size - (ofs + len)" which is a positive number. This is wrong. An easy way is to simply add an extra condition. In the unlock() path, if we can achieve the same result from both sides, it means we unlock everything and lock_len must simply be 0. A comment is added to clarify that logic.

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/spi-nor/swp.c

What this is

SPI NOR SUBSYSTEMMAINTAINERS section matched on drivers/mtd/spi-nor/ · linux-mtd@lists.infradead.org · Maintained

Kernel module

spi_nor

Check it on the machine

grep -wE 'CONFIG_MTD|CONFIG_MTD_SPI_NOR' /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 spi_nor

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, sidMnot 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_SPI_NOR

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

2026-08-15 (2 months ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.22%, higher than 11.3% 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
4.6	5.10.266	23c285be8f6f
4.6	5.15.217	a6fd2145c73b
4.6	6.1.178	9a0d8dec3d11
4.6	6.6.145	dc341272cf8e
4.6	6.12.97	6110ab5ffd84
4.6	6.18.40	c0806df5cf80
4.6	7.1.5	12d4d6922115
4.6	7.2	e1d456b26bf2