CVE-2026-89506

What the bug is

The original commit missed that three drivers (mthca, irdma, siw) have UHW data associated with reg_mr that cannot be passed through the ioctl. They also assume that the udata cannot be NULL, so failing to pass a valid udata can trigger a NULL udata crash in those drivers. This never happens in real systems since in rdma-core ibv_cmd_reg_mr_ex() does not accept a udata and those three drivers don't use it, however a malicious userspace could trigger it.

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/infiniband/core/uverbs_std_types_mr.c

What this is

INFINIBAND SUBSYSTEMMAINTAINERS section matched on drivers/infiniband/ · linux-rdma@vger.kernel.org · Supported

Kernel module

ib_uverbs

Check it on the machine

grep -wE 'CONFIG_INFINIBAND|CONFIG_INFINIBAND_USER_ACCESS' /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 ib_uverbs

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 as a loadable module. Every release below compiles it as a module on every flavour, so whether the code is in the running kernel depends on whether that module is loaded.

• bookworm, trixie, forky, sidm

m

a loadable module on every flavour - check lsmod, can be blacklisted

Build switches

CONFIG_INFINIBAND, CONFIG_INFINIBAND_USER_ACCESS

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

2026-09-11 (37 days ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.21%, higher than 10.0% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

unimportantsource

Subsystem

drivers/infiniband

Upstream fixes

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

Introduced	Fixed in	Commit
6.17	6.18.50	71d5c41ac583
6.17	7.2.4	9e71d0f4944b
6.17	7.3	011199f46f44