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CVE-2026-98990

namespace: check a submount for references right before unmounting it

Products / packages Linux

Published

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Severity and exploitation

Not in CISA KEVNo CVSS score

KEV coverage does not rule out exploitation.

KEV checked 14/11/2026, 21:40:35 UTC

Severity

unknown

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

16 ranges
Linux version evidence

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

affected

1064f874abc0d05eeed8993815f584d847b72486 → before cda0c4e502a0f74a191471ce100fb061e5ab35d6

git versions

1064f874abc0d05eeed8993815f584d847b72486 → before 3f55f71291e4332983cd63b288d1f2be3c9c08fc

git versions

1064f874abc0d05eeed8993815f584d847b72486 → before 361f59e7f3f9a219fb5567bf9abc8482a154a399

git versions

1064f874abc0d05eeed8993815f584d847b72486 → before f6394281834492c6516a405a348b545ae698a331

git versions

1064f874abc0d05eeed8993815f584d847b72486 → before 6e4012e571867868b545c91ca9d6095fdb709907

git versions

1064f874abc0d05eeed8993815f584d847b72486 → before d73f04e92c1aab78d96ac6cadb234c8a3a373d22

git versions

1064f874abc0d05eeed8993815f584d847b72486 → before 18902a23ef36f83d32bafc58ae2484e6bb4bb8ef

git versions

1064f874abc0d05eeed8993815f584d847b72486 → before 32bf92416614a1e3ff3524fc6b780259c7aad3ef

git versions

5e6ef5ef6eaf690faad3a7c6c665ebf45d7b6ccf

git versions

839d42687dfce0ed0ea2c6bd8d707cc0e276fbe7

git versions

808e83e5add13152bd4a88346487de68395c136b

git versions

6de9d08a9718ee9c12ba6343c50141c2d633e3dc

git versions

4.1.40 → before 4.2

semver versions

4.4.54 → before 4.5

semver versions

4.9.15 → before 4.10

semver versions

4.10.3 → before 4.11

semver versions

unaffected

unknown

Other versions: unaffected

Linux · Linux

Linux

10 ranges
Linux version evidence

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

affected

4.11

unaffected

0 → before 4.11

semver versions

5.10.273 → through 5.10.*

semver versions

5.15.224 → through 5.15.*

semver versions

6.1.191 → through 6.1.*

semver versions

6.6.160 → through 6.6.*

semver versions

6.12.113 → 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

unknown

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: check a submount for references right before unmounting it

shrink_submounts() and mark_mounts_for_expiry() first collect all the mounts they are allowed to unmount and then unmount them.

Whether a mount is busy is decided by propagate_mount_busy() on the tree. But unmounting the first mount changes the tree that the second one propagates into. propagate_umount() moves a surviving overmount off a copy it unmounts and mounts it where the copy was mounted. If that's where the propagated copy of the second victim is looked up the overmount becomes a candidate of the second umount_tree(). It's childless and so trim_one() commits it without looking at its reference count.

So a synchronous umount pulls out a busy mount that is in use somewhere else and marks it MNT_SYNC_UMOUNT while it has users:

umount2(/tmp/plshrink/p1, 0) = 0 errno 0 cwd is (unreachable)

The same two umounts requested one after the other fail with EBUSY. This needs a mount with MNT_SHRINKABLE, i.e., automounted submounts of NFS, AFS and CIFS or the tracefs mount below debugfs. Bind mounts inherit the flag.

Check each mount right before it is unmounted under the same hold of namespace_sem and mount_lock as the umount itself. Make sure that the algorithm stays linear.

References

8 sources
git.kernel.org/stable/c/cda0c4e502a0f74a191471ce100fb061e5ab35d6
Source referenceLinux
git.kernel.org/stable/c/3f55f71291e4332983cd63b288d1f2be3c9c08fc
Source referenceLinux
git.kernel.org/stable/c/361f59e7f3f9a219fb5567bf9abc8482a154a399
Source referenceLinux
git.kernel.org/stable/c/f6394281834492c6516a405a348b545ae698a331
Source referenceLinux
git.kernel.org/stable/c/6e4012e571867868b545c91ca9d6095fdb709907
Source referenceLinux
git.kernel.org/stable/c/d73f04e92c1aab78d96ac6cadb234c8a3a373d22
Source referenceLinux
View 2 more references
git.kernel.org/stable/c/18902a23ef36f83d32bafc58ae2484e6bb4bb8ef
Source referenceLinux
git.kernel.org/stable/c/32bf92416614a1e3ff3524fc6b780259c7aad3ef
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-2026-98990

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): 4.11

Before: 5.10.273

Vulnerable product

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

From (inclusive): 4.11

Before: 5.15.224

Vulnerable product

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

From (inclusive): 4.11

Before: 6.1.191

Vulnerable product

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

From (inclusive): 4.11

Before: 6.6.160

Vulnerable product

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

From (inclusive): 4.11

Before: 6.12.113

Vulnerable product

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

From (inclusive): 4.11

Before: 6.18.57

Vulnerable product

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

From (inclusive): 4.11

Before: 7.2.11

Vulnerable product

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

From (inclusive): 4.11

Before: 7.3

Vulnerable product

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

From (inclusive): 4.1.40

Vulnerable product

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

From (inclusive): 4.4.54

Vulnerable product

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

From (inclusive): 4.9.15

Vulnerable product

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

From (inclusive): 4.10.3

Applicability preview
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  {
    "nodes": [
      {
        "operator": "OR",
        "negate": false,
        "cpeMatch": [
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "4.11",
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          {
            "vulnerable": true,
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          {
            "vulnerable": true,
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          {
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          {
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          {
            "vulnerable": true,
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          {
            "vulnerable": true,
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          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "4.11",
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          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "4.1.40"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "4.4.54"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "4.9.15"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "4.10.3"
          }
        ]
      }
    ]
  }
]
Contributing organizations · 1
Linux

Assigning organization

2026-10-30

Timeline

All times UTC

  1. Advisory published

    Publication date supplied by the source.

  2. Source updated

    Latest modification date supplied by the source.

  3. 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.