CVE-2026-98994

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: statmount: read the parent of an unmounted mount under mount_lock statmount_mnt_basic() reads the ids of the parent through m->mnt_parent with namespace_sem held for reading. That's fine for a mount that is in a namespace. Everything above it is pinned by that namespace. STATMOUNT_BY_FD also accepts a file descriptor on a mount that has been unmounted on purpose and that only the file descriptor keeps alive. If that mount stayed attached to its parent when it was unmounted the parent is unmounted as well and nothing pins it for the child. The final mntput() unmounts the children under mount_lock alone and frees the parent afterwards. Concurrently, statmount_mnt_basic() reads m->mnt_parent twice while that can happen and can easily dereference a mount that's already gone. Read the parent of an unmounted mount under mount_lock. The parent can't be put while it is held and both ids come from the same mount. A mounted mount's parent is pinned by the namespace and a mount can't leave its namespace while namespace_sem is held, so the common case takes no global lock.

Severity

Not scored

CVSS score

Not available

Vulnerability status

Received

Source identifier

416baaa9-dc9f-4396-8d5f-8c081fb06d67

Published

2026-10-23 13:17:21.550000

Last modified

2026-10-23 13:17:21.550000

View original CVE JSON

{
  "id": "CVE-2026-98994",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-10-23T13:17:21.550",
  "lastModified": "2026-10-23T13:17:21.550",
  "vulnStatus": "Received",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nstatmount: read the parent of an unmounted mount under mount_lock\n\nstatmount_mnt_basic() reads the ids of the parent through m->mnt_parent\nwith namespace_sem held for reading. That's fine for a mount that is\nin a namespace. Everything above it is pinned by that namespace.\n\nSTATMOUNT_BY_FD also accepts a file descriptor on a mount that has\nbeen unmounted on purpose and that only the file descriptor keeps alive.\nIf that mount stayed attached to its parent when it was unmounted the\nparent is unmounted as well and nothing pins it for the child.\n\nThe final mntput() unmounts the children under mount_lock alone and\nfrees the parent afterwards. Concurrently, statmount_mnt_basic() reads\nm->mnt_parent twice while that can happen and can easily dereference a\nmount that's already gone.\n\nRead the parent of an unmounted mount under mount_lock. The parent\ncan't be put while it is held and both ids come from the same mount. A\nmounted mount's parent is pinned by the namespace and a mount can't\nleave its namespace while namespace_sem is held, so the common case\ntakes no global lock."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "fs/namespace.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "0e5032237ee5530147fbdf33134297e1490d5ec3",
              "lessThan": "98fc6c7b6ca676157d2c780bd0a537b2c10fe08f",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "0e5032237ee5530147fbdf33134297e1490d5ec3",
              "lessThan": "bb46094057520304073130920c223451c2a694a7",
              "versionType": "git",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "fs/namespace.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "7.0",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "7.0",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.2.11",
              "lessThanOrEqual": "7.2.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.3",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {},
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/98fc6c7b6ca676157d2c780bd0a537b2c10fe08f",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/bb46094057520304073130920c223451c2a694a7",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ]
}