CVE-2026-74395

What the bug is

MLX5_IB_METHOD_DEVX_SUBSCRIBE_EVENT() links event_sub into sub_list before initializing the fields used by the shared error path. If eventfd_ctx_fdget() then fails, the unwind path dereferences event_sub->ev_file in uverbs_uobject_put() and calls subscribe_event_xa_dealloc() with an unset xa_key_level1. subscribe_event_xa_alloc() creates the XA entry exactly once for a given key_level1, on the first occurrence of that key. The unwind path must therefore call subscribe_event_xa_dealloc() exactly once for it as well. Enforce that by adding devx_key_in_sub_list() and calling subscribe_event_xa_dealloc() only when the last matching pending entry is being cleaned up.

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/hw/mlx5/devx.c

What this is

MELLANOX MLX5 IB driverMAINTAINERS section matched on drivers/infiniband/hw/mlx5/ · linux-rdma@vger.kernel.org · Supported

Kernel module

mlx5_ib

Check it on the machine

grep -wE 'CONFIG_INFINIBAND|CONFIG_INFINIBAND_USER_ACCESS|CONFIG_MLX5_INFINIBAND' /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 mlx5_ib

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.

• bookwormm
• trixieMnot built on armel/rpi
• forky, sidm

m

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

M

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

Build switches

CONFIG_INFINIBAND, CONFIG_INFINIBAND_USER_ACCESS, CONFIG_MLX5_INFINIBAND

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 11.6% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

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
5.3	5.10.261	6e15b770461e
5.3	5.15.212	9be9aca28424
5.3	6.1.178	f345e744b6b0
5.3	6.6.145	1025dc2f7ba2
5.3	6.12.97	7921821fc2b1
5.3	6.18.40	5100febf8e9d
5.3	7.1.5	78b9589fda26
5.3	7.2	43f8f7946814