CVE-2026-89953

What the bug is

mtdoops_notify_add() allocates oops_page_used when the configured MTD device is registered. mtdoops_notify_remove() detaches from that device but leaves the bitmap allocated. If the same MTD device is later registered again, the add path allocates a new bitmap and overwrites the old pointer, leaking one vmalloc allocation per remove/add cycle. This is only visible when the backing MTD device can disappear and be registered again while mtdoops remains loaded, so the usual static MTD case does not expose it. Free the bitmap after unregistering the dumper and flushing the pending workers, then clear the pointer and page count before a later attach can allocate fresh state. Clearing the pointer also keeps the module exit path from freeing the same bitmap a second time after a remove event.

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/mtdoops.c

What this is

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

Kernel module

mtdoops

Check it on the machine

grep -wE 'CONFIG_MTD|CONFIG_MTD_OOPS' /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 mtdoops

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_OOPS

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

2026-09-16 (33 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
2.6.33	5.10.270	477d61d54e09
2.6.33	5.15.221	a91ac71e67c3
2.6.33	6.1.188	698944132083
2.6.33	6.6.157	f25c804947e0
2.6.33	6.12.110	8414f0e9f707
2.6.33	6.18.51	d06f91a52af1
2.6.33	7.2.5	1e5cd8bc9023
2.6.33	7.3	956e7da12c11

Debian advisories