From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-cve-announce@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@kernel.org>
Subject: CVE-2026-89445: iommufd: Fix UAF in selftest IOPF reporting
Date: Fri, 11 Sep 2026 21:42:14 +0200 [thread overview]
Message-ID: <2026091157-CVE-2026-89445-c2c8@gregkh> (raw)
From: Greg Kroah-Hartman <gregkh@kernel.org>
Description
===========
In the Linux kernel, the following vulnerability has been resolved:
iommufd: Fix UAF in selftest IOPF reporting
IOMMUFD selftest TRIGGER_IOPF borrows an attach handle from
group->pasid_array without synchronizing against PASID detach,
then a concurrent iommu_report_device_fault() can dereference
that borrowed handle's domain pointer after the detach erases
the handle and frees the backing struct iommufd_attach_handle.
TRIGGER_IOPF then dereferences the freed handle, causing a UAF.
Fix by adding a iopf_rwsem in mock_dev to follow the expected design
of a real driver. Hold its read side across the whole
iommu_report_device_fault() call, and its write side around every
path that attaches, detaches, or replaces a device domain.
This can block new reports and drains in-flight reports before an old
attach handle or the IOPF fault parameter can be removed.
Also take the write side while registering a mock device, since
it can invoke the mock driver's default-domain attach callback.
The Linux kernel CVE team has assigned CVE-2026-89445 to this issue.
Affected and fixed versions
===========================
Issue introduced in 6.11 with commit ddee19971081b42615d62f4fdada21274708ed4d and fixed in 6.18.50 with commit cab2895729516799384d48560e6fca105fb3f927
Issue introduced in 6.11 with commit ddee19971081b42615d62f4fdada21274708ed4d and fixed in 7.2.4 with commit e27e90bde68b2ab92e63ed19caad1ef57188bea0
Issue introduced in 6.11 with commit ddee19971081b42615d62f4fdada21274708ed4d and fixed in 7.3-rc1 with commit 8c07df7cdfcf52f1ff276c588612aabc6c6b8399
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-2026-89445
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/iommufd/selftest.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/cab2895729516799384d48560e6fca105fb3f927
https://git.kernel.org/stable/c/e27e90bde68b2ab92e63ed19caad1ef57188bea0
https://git.kernel.org/stable/c/8c07df7cdfcf52f1ff276c588612aabc6c6b8399
reply other threads:[~2026-09-11 19:52 UTC|newest]
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