CVE-2026-98978

namespace: never expire a locked mount

Products / packages Linux

Published 23/10/2026, 12:19:51 UTC

Severity and exploitation

Not in CISA KEV

KEV coverage does not rule out exploitation.

KEV checked 14/11/2026, 21:00:34 UTC

Linux · CVSS:3.1 · 8.4

Assessment vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N

Severity

high8.4

CVSS measures technical severity, not the likelihood of an attack.

Known exploitation

Not listed in the checked CISA KEV catalog

Absence from CISA KEV does not rule out attacks.

Public exploit

Not established by this record

Missing evidence does not mean no public exploit exists.

Remediation

Fix status not established

No structured fix or guidance is available here. Check the latest publisher advisory.

What this means

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

Source excerpt · Linux

Attack conditions

No attack-condition excerpt has been identified here. Review the full source description and references for authentication, network access, and configuration requirements.

Review supporting sources →

Affected versions

Check the exact model, release, and any platform requirements against your installation.

Linux · Linux

Linux

4 ranges

Linux version evidence

Check a product version

Compare with this publisher’s ranges. This does not inspect your installation.

affected

5ff9d8a65ce80efb509ce4e8051394e9ed2cd942 → before 6c8013ea84fcc51cf26aa870b61b5388c7196ed5

git versions

5ff9d8a65ce80efb509ce4e8051394e9ed2cd942 → before 6b8dc3713a76346d212abab46cbfc8d7070f534c

git versions

5ff9d8a65ce80efb509ce4e8051394e9ed2cd942 → before d23265a12e4991ce7aedce670c0b6b598cadb644

git versions

5ff9d8a65ce80efb509ce4e8051394e9ed2cd942 → before f78ddcc872248c7aa1d7e904928441a0be4c6d5d

git versions

Other versions: unaffected

Linux · Linux

Linux

6 ranges

Linux version evidence

Check a product version

Compare with this publisher’s ranges. This does not inspect your installation.

affected

3.12

unaffected

0 → before 3.12

semver versions

6.12.117 → through 6.12.*

semver versions

6.18.57 → through 6.18.*

semver versions

7.2.11 → through 7.2.*

semver versions

7.3 → through *

original_commit_for_fix versions

Other versions: affected

Automatic dependency matching is unavailable for this record. Use the product evidence and publisher’s instructions to check your installation.

What to do

Compare your installed product and version with the affected versions above. A matching product name alone does not confirm exposure.

No structured fix or remediation guidance is available here. Check the full source description and vendor’s latest advisory for a patch or workaround; do not assume another version is safe.

cve.new guidance unless attributed to a publisher. This page does not inspect your installation.

Public exploit evidence

No public exploit reference is identified in the imported evidence. This is not a claim that no exploit exists.

Original source description

Read the full publisher description

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

namespace: never expire a locked mount

Locked mounts are special. They protect the underlying files and directories from being revealed. do_umount() refuses to unmount locked mounts but shrink_submounts() doesn't.

A shrinkable mount can become locked once the owner of a user namespace puts it beneath a locked mount with MOVE_MOUNT_BENEATH. The locked property now moves to the mount at the bottom making it possible to unmount the top mount.

So umount() of an unlocked ancestor now expires the bottom mount first and the covered directory is revealed:

move_mount(c -> x/hidden, MOVE_MOUNT_BENEATH) = 0 the cover after the lock moved: umount2(x/hidden) = 0 the holder of the lock: umount2(x/hidden) = EINVAL the root of the copy, busy: umount2(x) = EBUSY reads x/hidden/secret: "covered-by-root"

So leave a locked mount alone as it dies together with its parent. A plain umount() of an unlocked mount with a locked one below it is EBUSY from now on. It's the same for any other locked child. A lazy umount still takes the whole tree.

mark_mounts_for_expiry() never sees a locked mount. lock_mnt_tree() leaves a mount on an expiry list alone and nothing else puts a locked one on such a list. Add an assert for this.

References

4 sources

git.kernel.org/stable/c/6c8013ea84fcc51cf26aa870b61b5388c7196ed5

Source referenceLinux

git.kernel.org/stable/c/6b8dc3713a76346d212abab46cbfc8d7070f534c

Source referenceLinux

git.kernel.org/stable/c/d23265a12e4991ce7aedce670c0b6b598cadb644

Source referenceLinux

git.kernel.org/stable/c/f78ddcc872248c7aa1d7e904928441a0be4c6d5d

Source referenceLinux

Inside the record

Evidence available

Package identity · not supplied

Version evidence

Remediation guidance · not supplied

Weakness classification · not supplied

Additional publishers · not supplied

Describes the evidence in this view, not whether the product is safe.

Original records

CVE-2026-98978

View the latest unmodified CVE JSON from the official source. It may be newer than this imported page.

cve.new JSON →

Environment requirements

These conditions apply together as specified by the publisher. A matching product name alone does not establish exposure.

Linux · platform conditions

Any condition may hold

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 3.12

After:

Through (inclusive):

Before: 6.12.117

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 3.12

After:

Through (inclusive):

Before: 6.18.57

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 3.12

After:

Through (inclusive):

Before: 7.2.11

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 3.12

After:

Through (inclusive):

Before: 7.3

Applicability preview

[
  {
    "nodes": [
      {
        "operator": "OR",
        "negate": false,
        "cpeMatch": [
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "3.12",
            "versionEndExcluding": "6.12.117"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "3.12",
            "versionEndExcluding": "6.18.57"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "3.12",
            "versionEndExcluding": "7.2.11"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "3.12",
            "versionEndExcluding": "7.3"
          }
        ]
      }
    ]
  }
]

Contributing organizations · 1

Linux

Assigning organization

2026-11-10

Timeline

All times UTC

23 Oct 2026, 12:19
Advisory published
Publication date supplied by the source.
10 Nov 2026, 18:15
Source updated
Latest modification date supplied by the source.
10 Nov 2026, 18:25
Last imported by cve.new
Latest catalog import, not the date we first saw this advisory.

What changed

Follow changes

No substantive changes have been recorded here yet. History starts when cve.new observes a change after tracking is enabled; earlier edits are not reconstructed.

Large field values are marked as truncated previews. Original source snapshots remain retained.

Reading the signals

Severity · CVSS: Technical impact and attack conditions. The headline is the highest imported catalog score; sources may disagree.
Observed exploitation · KEV: An absent or unavailable KEV listing does not establish that exploitation has not occurred.
Predicted exploitation · EPSS: No EPSS estimate available in this record.

Record identifiers

Aliases: None recorded

Source evidence

Request a correction or dispute

Start with the assigning organization for this record. Include the CVE ID, the disputed information, and supporting evidence. A dispute does not itself reject a record.

Find the responsible CNA →Official dispute and escalation process ↗

CVE CVE-2026-98978

Enrichment coverage

NVDNot fully checked

GHSANot fully checked

EUVDNot fully checked

EPSSNot fully checked

Sponsored by MoxsoBuild security habits with adaptive training and phishing simulations.View as JSON

Investigate in your agent.

namespace: never expire a locked mount

Severity and exploitation

What this means

Attack conditions

Affected versions

Linux

affected

unaffected

unknown

Linux

affected

unaffected

unknown

What to do

Public exploit evidence

Original source description

References

Inside the record

Evidence available

Original records

Environment requirements

Timeline

Advisory published

Source updated

Last imported by cve.new

What changed