CVE-2026-89445

iommufd: Fix UAF in selftest IOPF reporting

Published Sep 11, 2026 CVSS 3.1 · 8.8 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

Sign in to view the affected projects.

Advisories

Source ID Title
Debian DLA Debian DLA DLA-4850-1 linux-6.12 security update
Debian DSA Debian DSA DSA-6568-1 linux security update
Ubuntu USN Ubuntu USN USN-9019-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-9020-1 Linux kernel vulnerabilities
History
Type Values Removed Values Added
Metrics cvssV3_1

{'score': 4.1, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H'}

cvssV3_1

{'score': 8.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H'}

Type Values Removed Values Added
Weaknesses CWE-825
References
Metrics threat_severity

None

cvssV3_1

{'score': 4.1, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate

Type Values Removed Values Added
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.
Title iommufd: Fix UAF in selftest IOPF reporting
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
Oct 19, 2026, 8:46 AM
Reserved
Sep 11, 2026, 7:38 PM
Status
Received
Published
Sep 11, 2026, 8:19 PM
Modified
Oct 19, 2026, 9:17 AM
Severity
Moderate
Public date
Sep 11, 2026, 7:43 PM