Vulnerability-Lookup

CVE-2026-98979 (GCVE-0-2026-98979)

Vulnerability from cvelistv5 – Published: 2026-10-23 12:19 – Updated: 2026-10-23 12:19

Title

namespace: refuse an automount below a mount that is in no namespace

Summary

In the Linux kernel, the following vulnerability has been resolved: namespace: refuse an automount below a mount that is in no namespace It's possible to add autmounts even when the parent mount isn't in the mount namespace of the caller. The only requirement we have is that the parent mount namespace must not be NULL, i.e., unmounted. Problem is that clone_private_mount() has MNT_NS_INTERNAL which makes that trivially true. So that passes the test and attach_recursive_mnt() accepts that as a mount point and funny enough, count_mounts() dereferences MNT_NS_INTERNAL. The problem is it is an error pointer... So we can reach this in userspace via fanotify. A filesystem mark on the lower filesystem of an overlay reports paths on the layer clone and reading the event hands out a descriptor on it. For example with debugfs as the lower layer it goes kaboom: openat(evfd, "tracing", O_DIRECTORY) Oops: general protection fault KASAN: null-ptr-deref in range [0x1d0-0x1d7] RIP: 0010:count_mounts+0x35/0x200 attach_recursive_mnt finish_automount And since that sleeping beauty happens under namespace_sem held for writing every mount operation on the system blocks from then on. Congrats. Use is_mounted() instead which rejects unmounted and internal mounts alike. The open fails with EINVAL just as it did before clone_private_mount() used MNT_NS_INTERNAL.

Severity

No CVSS data available.

Assigner

Linux CNA under the mitre root

CNA scorecard D 53/100 over 7061 records in the last 180 days details

References

5 references

URL	Tags
https://git.kernel.org/stable/c/95fb7c259b86f5521…
https://git.kernel.org/stable/c/35f2013f83ef16f9f…
https://git.kernel.org/stable/c/494c57572d2d5bc28…
https://git.kernel.org/stable/c/776e20e4fdc23c236…
https://git.kernel.org/stable/c/ba985ce08471c555a…

Impacted products

2 products

Vendor	Product	Version	CPE status
Linux	Linux	Affected: df820f8de4e481222b17f9bcee7b909ae8167529 , < 95fb7c259b86f5521f04973040ad492f2bef6f82 (git) Affected: df820f8de4e481222b17f9bcee7b909ae8167529 , < 35f2013f83ef16f9f0331c4c3a8e8d161580d574 (git) Affected: df820f8de4e481222b17f9bcee7b909ae8167529 , < 494c57572d2d5bc2839553ed41aabe92ed0f587c (git) Affected: df820f8de4e481222b17f9bcee7b909ae8167529 , < 776e20e4fdc23c23687b511ffdc80047878049d3 (git) Affected: df820f8de4e481222b17f9bcee7b909ae8167529 , < ba985ce08471c555af2a2fbe217c1bc2e72a6d8c (git)	guessed
Linux	Linux	Affected: 5.8 Unaffected: 0 , < 5.8 (semver) Unaffected: 6.6.160 , ≤ 6.6.* (semver) Unaffected: 6.12.113 , ≤ 6.12.* (semver) Unaffected: 6.18.57 , ≤ 6.18.* (semver) Unaffected: 7.2.11 , ≤ 7.2.* (semver) Unaffected: 7.3 , ≤ * (original_commit_for_fix)	guessed

Show details on NVD website

JSON

To clipboard

{
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        {
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          "product": "Linux",
          "programFiles": [
            "fs/namespace.c"
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          "programFiles": [
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          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.8"
            },
            {
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "6.6.160",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.113",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "6.18.57",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.11",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnamespace: refuse an automount below a mount that is in no namespace\n\nIt\u0027s possible to add autmounts even when the parent mount isn\u0027t in the\nmount namespace of the caller. The only requirement we have is that the\nparent mount namespace must not be NULL, i.e., unmounted.\n\nProblem is that clone_private_mount() has MNT_NS_INTERNAL which makes\nthat trivially true. So that passes the test and attach_recursive_mnt()\naccepts that as a mount point and funny enough, count_mounts()\ndereferences MNT_NS_INTERNAL. The problem is it is an error pointer...\n\nSo we can reach this in userspace via fanotify. A filesystem mark on the\nlower filesystem of an overlay reports paths on the layer clone and\nreading the event hands out a descriptor on it. For example with debugfs\nas the lower layer it goes kaboom:\n\n  openat(evfd, \"tracing\", O_DIRECTORY)\n\n  Oops: general protection fault\n  KASAN: null-ptr-deref in range [0x1d0-0x1d7]\n  RIP: 0010:count_mounts+0x35/0x200\n   attach_recursive_mnt\n   finish_automount\n\nAnd since that sleeping beauty happens under namespace_sem held for\nwriting every mount operation on the system blocks from then on.\nCongrats.\n\nUse is_mounted() instead which rejects unmounted and internal mounts\nalike. The open fails with EINVAL just as it did before\nclone_private_mount() used MNT_NS_INTERNAL."
        }
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        },
        {
          "url": "https://git.kernel.org/stable/c/776e20e4fdc23c23687b511ffdc80047878049d3"
        },
        {
          "url": "https://git.kernel.org/stable/c/ba985ce08471c555af2a2fbe217c1bc2e72a6d8c"
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      "title": "namespace: refuse an automount below a mount that is in no namespace",
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    "cveId": "CVE-2026-98979",
    "datePublished": "2026-10-23T12:19:52.523Z",
    "dateReserved": "2026-09-25T10:25:14.383Z",
    "dateUpdated": "2026-10-23T12:19:52.523Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": {
      "cve": {
        "affected": [
          {
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                "product": "Linux",
                "programFiles": [
                  "fs/namespace.c"
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                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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                    "versionType": "git"
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                  {
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                    "versionType": "git"
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                "versions": [
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                    "status": "affected",
                    "version": "5.8"
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                    "status": "unaffected",
                    "version": "0",
                    "versionType": "semver"
                  },
                  {
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                    "status": "unaffected",
                    "version": "6.6.160",
                    "versionType": "semver"
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                  {
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                    "status": "unaffected",
                    "version": "6.12.113",
                    "versionType": "semver"
                  },
                  {
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                    "versionType": "semver"
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        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnamespace: refuse an automount below a mount that is in no namespace\n\nIt\u0027s possible to add autmounts even when the parent mount isn\u0027t in the\nmount namespace of the caller. The only requirement we have is that the\nparent mount namespace must not be NULL, i.e., unmounted.\n\nProblem is that clone_private_mount() has MNT_NS_INTERNAL which makes\nthat trivially true. So that passes the test and attach_recursive_mnt()\naccepts that as a mount point and funny enough, count_mounts()\ndereferences MNT_NS_INTERNAL. The problem is it is an error pointer...\n\nSo we can reach this in userspace via fanotify. A filesystem mark on the\nlower filesystem of an overlay reports paths on the layer clone and\nreading the event hands out a descriptor on it. For example with debugfs\nas the lower layer it goes kaboom:\n\n  openat(evfd, \"tracing\", O_DIRECTORY)\n\n  Oops: general protection fault\n  KASAN: null-ptr-deref in range [0x1d0-0x1d7]\n  RIP: 0010:count_mounts+0x35/0x200\n   attach_recursive_mnt\n   finish_automount\n\nAnd since that sleeping beauty happens under namespace_sem held for\nwriting every mount operation on the system blocks from then on.\nCongrats.\n\nUse is_mounted() instead which rejects unmounted and internal mounts\nalike. The open fails with EINVAL just as it did before\nclone_private_mount() used MNT_NS_INTERNAL."
          }
        ],
        "id": "CVE-2026-98979",
        "lastModified": "2026-10-23T13:17:19.627",
        "metrics": {},
        "published": "2026-10-23T13:17:19.627",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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          },
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          },
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            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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        "vulnStatus": "Received"
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}

FKIE_CVE-2026-98979

Vulnerability from fkie_nvd - Published: 2026-10-23 13:17 - Updated: 2026-10-23 13:17

Severity

Summary

References

	URL	Tags
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/35f2013f83ef16f9f0331c4c3a8e8d161580d574
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/494c57572d2d5bc2839553ed41aabe92ed0f587c
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/776e20e4fdc23c23687b511ffdc80047878049d3
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/95fb7c259b86f5521f04973040ad492f2bef6f82
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/ba985ce08471c555af2a2fbe217c1bc2e72a6d8c

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/namespace.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "95fb7c259b86f5521f04973040ad492f2bef6f82",
              "status": "affected",
              "version": "df820f8de4e481222b17f9bcee7b909ae8167529",
              "versionType": "git"
            },
            {
              "lessThan": "35f2013f83ef16f9f0331c4c3a8e8d161580d574",
              "status": "affected",
              "version": "df820f8de4e481222b17f9bcee7b909ae8167529",
              "versionType": "git"
            },
            {
              "lessThan": "494c57572d2d5bc2839553ed41aabe92ed0f587c",
              "status": "affected",
              "version": "df820f8de4e481222b17f9bcee7b909ae8167529",
              "versionType": "git"
            },
            {
              "lessThan": "776e20e4fdc23c23687b511ffdc80047878049d3",
              "status": "affected",
              "version": "df820f8de4e481222b17f9bcee7b909ae8167529",
              "versionType": "git"
            },
            {
              "lessThan": "ba985ce08471c555af2a2fbe217c1bc2e72a6d8c",
              "status": "affected",
              "version": "df820f8de4e481222b17f9bcee7b909ae8167529",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/namespace.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.8"
            },
            {
              "lessThan": "5.8",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.160",
              "versionType": "semver"
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            {
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              "status": "unaffected",
              "version": "6.12.113",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "6.18.57",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.11",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnamespace: refuse an automount below a mount that is in no namespace\n\nIt\u0027s possible to add autmounts even when the parent mount isn\u0027t in the\nmount namespace of the caller. The only requirement we have is that the\nparent mount namespace must not be NULL, i.e., unmounted.\n\nProblem is that clone_private_mount() has MNT_NS_INTERNAL which makes\nthat trivially true. So that passes the test and attach_recursive_mnt()\naccepts that as a mount point and funny enough, count_mounts()\ndereferences MNT_NS_INTERNAL. The problem is it is an error pointer...\n\nSo we can reach this in userspace via fanotify. A filesystem mark on the\nlower filesystem of an overlay reports paths on the layer clone and\nreading the event hands out a descriptor on it. For example with debugfs\nas the lower layer it goes kaboom:\n\n  openat(evfd, \"tracing\", O_DIRECTORY)\n\n  Oops: general protection fault\n  KASAN: null-ptr-deref in range [0x1d0-0x1d7]\n  RIP: 0010:count_mounts+0x35/0x200\n   attach_recursive_mnt\n   finish_automount\n\nAnd since that sleeping beauty happens under namespace_sem held for\nwriting every mount operation on the system blocks from then on.\nCongrats.\n\nUse is_mounted() instead which rejects unmounted and internal mounts\nalike. The open fails with EINVAL just as it did before\nclone_private_mount() used MNT_NS_INTERNAL."
    }
  ],
  "id": "CVE-2026-98979",
  "lastModified": "2026-10-23T13:17:19.627",
  "metrics": {},
  "published": "2026-10-23T13:17:19.627",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/35f2013f83ef16f9f0331c4c3a8e8d161580d574"
    },
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    },
    {
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    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ba985ce08471c555af2a2fbe217c1bc2e72a6d8c"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}

GHSA-XHGJ-MP6G-FW2X

Vulnerability from github – Published: 2026-10-23 15:31 – Updated: 2026-10-23 15:31

Details

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

namespace: refuse an automount below a mount that is in no namespace

It's possible to add autmounts even when the parent mount isn't in the mount namespace of the caller. The only requirement we have is that the parent mount namespace must not be NULL, i.e., unmounted.

Problem is that clone_private_mount() has MNT_NS_INTERNAL which makes that trivially true. So that passes the test and attach_recursive_mnt() accepts that as a mount point and funny enough, count_mounts() dereferences MNT_NS_INTERNAL. The problem is it is an error pointer...

So we can reach this in userspace via fanotify. A filesystem mark on the lower filesystem of an overlay reports paths on the layer clone and reading the event hands out a descriptor on it. For example with debugfs as the lower layer it goes kaboom:

openat(evfd, "tracing", O_DIRECTORY)

Oops: general protection fault KASAN: null-ptr-deref in range [0x1d0-0x1d7] RIP: 0010:count_mounts+0x35/0x200 attach_recursive_mnt finish_automount

And since that sleeping beauty happens under namespace_sem held for writing every mount operation on the system blocks from then on. Congrats.

Use is_mounted() instead which rejects unmounted and internal mounts alike. The open fails with EINVAL just as it did before clone_private_mount() used MNT_NS_INTERNAL.

Show details on source website

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{
  "affected": [],
  "aliases": [
    "CVE-2026-98979"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-23T13:17:19Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnamespace: refuse an automount below a mount that is in no namespace\n\nIt\u0027s possible to add autmounts even when the parent mount isn\u0027t in the\nmount namespace of the caller. The only requirement we have is that the\nparent mount namespace must not be NULL, i.e., unmounted.\n\nProblem is that clone_private_mount() has MNT_NS_INTERNAL which makes\nthat trivially true. So that passes the test and attach_recursive_mnt()\naccepts that as a mount point and funny enough, count_mounts()\ndereferences MNT_NS_INTERNAL. The problem is it is an error pointer...\n\nSo we can reach this in userspace via fanotify. A filesystem mark on the\nlower filesystem of an overlay reports paths on the layer clone and\nreading the event hands out a descriptor on it. For example with debugfs\nas the lower layer it goes kaboom:\n\n  openat(evfd, \"tracing\", O_DIRECTORY)\n\n  Oops: general protection fault\n  KASAN: null-ptr-deref in range [0x1d0-0x1d7]\n  RIP: 0010:count_mounts+0x35/0x200\n   attach_recursive_mnt\n   finish_automount\n\nAnd since that sleeping beauty happens under namespace_sem held for\nwriting every mount operation on the system blocks from then on.\nCongrats.\n\nUse is_mounted() instead which rejects unmounted and internal mounts\nalike. The open fails with EINVAL just as it did before\nclone_private_mount() used MNT_NS_INTERNAL.",
  "id": "GHSA-xhgj-mp6g-fw2x",
  "modified": "2026-10-23T15:31:33Z",
  "published": "2026-10-23T15:31:33Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98979"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/35f2013f83ef16f9f0331c4c3a8e8d161580d574"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/494c57572d2d5bc2839553ed41aabe92ed0f587c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/776e20e4fdc23c23687b511ffdc80047878049d3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/95fb7c259b86f5521f04973040ad492f2bef6f82"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ba985ce08471c555af2a2fbe217c1bc2e72a6d8c"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

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CVE-2026-98979 (GCVE-0-2026-98979)

FKIE_CVE-2026-98979

GHSA-XHGJ-MP6G-FW2X

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