linux-cve-announce - CVE-2026-23174: nvme-pci: handle changing device dma map requirements

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Message-ID: <2026021427-CVE-2026-23174-0b41@gregkh>
Date: Sat, 14 Feb 2026 17:28:31 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2026-23174: nvme-pci: handle changing device dma map requirements

From: Greg Kroah-Hartman <gregkh@...nel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

nvme-pci: handle changing device dma map requirements

The initial state of dma_needs_unmap may be false, but change to true
while mapping the data iterator. Enabling swiotlb is one such case that
can change the result. The nvme driver needs to save the mapped dma
vectors to be unmapped later, so allocate as needed during iteration
rather than assume it was always allocated at the beginning. This fixes
a NULL dereference from accessing an uninitialized dma_vecs when the
device dma unmapping requirements change mid-iteration.

The Linux kernel CVE team has assigned CVE-2026-23174 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 6.17 with commit b8b7570a7ec872f2a27b775c4f8710ca8a357adf and fixed in 6.18.10 with commit f3ed399e9aa6f36e92d2d0fe88b387915e9705fe
	Issue introduced in 6.17 with commit b8b7570a7ec872f2a27b775c4f8710ca8a357adf and fixed in 6.19 with commit 071be3b0b6575d45be9df9c5b612f5882bfc5e88

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-23174
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/nvme/host/pci.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/f3ed399e9aa6f36e92d2d0fe88b387915e9705fe
	https://git.kernel.org/stable/c/071be3b0b6575d45be9df9c5b612f5882bfc5e88