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iommufd: Avoid locking internal accesses during unmap

Type: advisorySources: OSV

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.

Products
Kernel
Affected versions
Not specified
Fixed versions
6.18.50, 7.2.4
CVEs
CVE-2026-89447
Confirmed fixed CVEs
Not specified
Updated in this feed
4 Nov 2026, 19:44 UTC · Revision 1

Source evidence

iommufd: Avoid locking internal accesses during unmap

core-osv · Original source

Published 11 Sept 2026, 19:43 UTC

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.

osv:CVE-2026-89447

Kernel

Fixed versions: 6.18.50, 7.2.4

Complete source record
{
  "id": "9c1d3a18c208e9600038f6d84ced8ec9425c9812fffa8615d083a8094e84ff40",
  "url": "https://osv.dev/vulnerability/CVE-2026-89447",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "iommufd: Avoid locking internal accesses during unmap",
    "summary": "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.",
    "evidence": "osv:CVE-2026-89447",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.18.50",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.2.4",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-89447",
      "aliases": [
        "CVE-2026-89447"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "27b77ea5feaa8fcf385ea99ce757982b0ac9d1f0"
                },
                {
                  "fixed": "436189ee4bb2c7c993b945d68570dd38c3e4349e"
                },
                {
                  "fixed": "50a66a63d1c841ae6b28a4551f642c1bba4c9529"
                },
                {
                  "fixed": "0dbcdf4473a614adbd732d567c9b39ac0e040e0c"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89447.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.17.0"
                },
                {
                  "fixed": "6.18.50"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "7.2.4"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89447.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:38.742048262Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/0dbcdf4473a614adbd732d567c9b39ac0e040e0c",
        "https://git.kernel.org/stable/c/436189ee4bb2c7c993b945d68570dd38c3e4349e",
        "https://git.kernel.org/stable/c/50a66a63d1c841ae6b28a4551f642c1bba4c9529",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89447.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-89447",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89447.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-89447",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 506313,
  "published_at": "2026-09-11T19:43:14.094+00:00"
}