CVE-2026-64152: iommu: Handle unmap error when iommu_debug is enabled

Greg Kroah-Hartman <[email protected]>
Newsgroups org.kernel.vger.linux-cve-announce
Message-ID <2026071931-CVE-2026-64152-0751@gregkh>
From: Greg Kroah-Hartman <[email protected]>

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

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

iommu: Handle unmap error when iommu_debug is enabled

Sashiko noticed a latent bug where the map error flow called iommu_unmap()
which calls iommu_debug_unmap_begin()/iommu_debug_unmap_end() however
since this is an error path the map flow never actually established the
original iommu_debug_map() it will malfunction.

Lift the unmap error handling into iommu_map_nosync() and reorder it so
the trace_map()/iommu_debug_map() records the partial mapping and then
immediately unmaps it. This avoid creating the unbalanced tracking and
provides saner tracing instead of a unmap unmatched to any map.

The Linux kernel CVE team has assigned CVE-2026-64152 to this issue.


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

	Issue introduced in 7.0 with commit ccc21213f013834b484cdcc738e282f963fcfc97 and fixed in 7.0.11 with commit 0cd028806efc148a75d4acf711d21db335a89661
	Issue introduced in 7.0 with commit ccc21213f013834b484cdcc738e282f963fcfc97 and fixed in 7.1 with commit 0735c54804c709d1b292f3b6947cfb560b2ce552

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-2026-64152
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/iommu/iommu.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/0cd028806efc148a75d4acf711d21db335a89661
	https://git.kernel.org/stable/c/0735c54804c709d1b292f3b6947cfb560b2ce552
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