landlock: Require LANDLOCK_ACCESS_FS_MAKE_REG for whiteout creation

{
  "id": "34c3eacc609fe5a709f469d3d3b33f02ae3b8497bb52d5ff01a0fd491591036d",
  "url": "https://osv.dev/vulnerability/CVE-2026-89560",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "landlock: Require LANDLOCK_ACCESS_FS_MAKE_REG for whiteout creation",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: landlock: Require LANDLOCK_ACCESS_FS_MAKE_REG for whiteout creation Whiteout objects are used in the upper layer of an OverlayFS to indicate that the file with this name does not exist in the unified view, even if it is present in one of the lower layer file systems. For the userspace implementations of OverlayFS (fuse-overlayfs), whiteout objects can be created from userspace as well: * mknod(2) with S_IFCHR and makedev(0, 0) * renameat2(2) with RENAME_WHITEOUT, creating the whiteout in the old place of the moved file. This commit guards whiteout creation in both of these cases with LANDLOCK_ACCESS_FS_MAKE_REG. Whiteout objects are *not* considered character devices and are not bound to a driver. LANDLOCK_ACCESS_FS_MAKE_REG describes the same permission class as a whiteout object: creating one is the only S_IFCHR creation that the VFS exempts from CAP_MKNOD, so it is as unprivileged as creating a regular file, while LANDLOCK_ACCESS_FS_MAKE_CHAR and LANDLOCK_ACCESS_FS_MAKE_BLOCK keep meaning the creation of devices that expose a kernel interface [1]. For the mknod(2) case, introduce a Landlock erratum. The creation of whiteout objects through mknod(2) was previously guarded using LANDLOCK_ACCESS_FS_MAKE_CHAR, and it is now guarded using LANDLOCK_ACCESS_FS_MAKE_REG. For the renameat2(2) case, fix a bug: Before this commit, renameat2(2) with RENAME_WHITEOUT would create a directory entry even when all LANDLOCK_",
    "evidence": "osv:CVE-2026-89560",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.15.222",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.188",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.157",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.110",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.50",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.2.4",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-89560",
      "aliases": [
        "CVE-2026-89560"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "cb2c7d1a1776057c9a1f48ed1250d85e94d4850d"
                },
                {
                  "fixed": "39fc16597715125529df8f94e016fb00836ee3c1"
                },
                {
                  "fixed": "d739e32318479086efb8a6bcf5d37cf341b51f8f"
                },
                {
                  "fixed": "dfb10d989056181168ebc16781a8f39520e33200"
                },
                {
                  "fixed": "efb4f24fc2b9bcef1c41ff3392894f1fa8fba2a0"
                },
                {
                  "fixed": "627ce4902df1d737e99306daae5a87c68b876d16"
                },
                {
                  "fixed": "0c3204aacbe8c07f9e87e3028f28ec6c166a1075"
                },
                {
                  "fixed": "672fa082d48b21e1fb62cdb184fee41513e53421"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89560.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.13.0"
                },
                {
                  "fixed": "5.15.222"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.16.0"
                },
                {
                  "fixed": "6.1.188"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.2.0"
                },
                {
                  "fixed": "6.6.157"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.7.0"
                },
                {
                  "fixed": "6.12.110"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "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-2026-89560.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:37.973325504Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/0c3204aacbe8c07f9e87e3028f28ec6c166a1075",
        "https://git.kernel.org/stable/c/39fc16597715125529df8f94e016fb00836ee3c1",
        "https://git.kernel.org/stable/c/627ce4902df1d737e99306daae5a87c68b876d16",
        "https://git.kernel.org/stable/c/672fa082d48b21e1fb62cdb184fee41513e53421",
        "https://git.kernel.org/stable/c/d739e32318479086efb8a6bcf5d37cf341b51f8f",
        "https://git.kernel.org/stable/c/dfb10d989056181168ebc16781a8f39520e33200",
        "https://git.kernel.org/stable/c/efb4f24fc2b9bcef1c41ff3392894f1fa8fba2a0",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89560.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-89560",
        "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-2026-89560.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-89560",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 505418,
  "published_at": "2026-09-11T19:44:32.085+00:00"
}