# CVE-2026-89445

## Summary

- **CVE ID:** CVE-2026-89445
- **Severity:** HIGH
- **CVSS Score:** 8.8 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H)
- **CWE:** N/A
- **Published:** Sep 11, 2026
- **Last Modified:** Sep 13, 2026

## 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.

## Affected Products

- Linux — Linux (ddee19971081b42615d62f4fdada21274708ed4d)
- Linux — Linux (6.11)
- Linux — Linux (0)
- Linux — Linux (6.18.50)
- Linux — Linux (7.2.4)
- Linux — Linux (7.3-rc1)

## References

- [CNA](https://git.kernel.org/stable/c/cab2895729516799384d48560e6fca105fb3f927)
- [CNA](https://git.kernel.org/stable/c/e27e90bde68b2ab92e63ed19caad1ef57188bea0)
- [CNA](https://git.kernel.org/stable/c/8c07df7cdfcf52f1ff276c588612aabc6c6b8399)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.16%
- **EPSS Percentile:** 5.7

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._