CVE-2026-89447

/// Technical description

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

iommufd: Avoid locking internal accesses during unmap

iommufd_access_notify_unmap() skips internal accesses because they do

not have an external unmap callback to invoke.

However, the current test calls iommufd_lock_obj() before checking

whether the access is internal. If iommufd_lock_obj() succeeds, the loop

then sees the internal access and continues, bypassing the matching

iommufd_put_object() used by the normal unmap path. This leaks the

object reference taken by iommufd_lock_obj().

Check for internal accesses first so skipped entries are never locked.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References