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CVE-2026-98977

namespace: handle mount locking for automounts correctly

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, 21:05:32 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

10 ranges
Linux version evidence

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

affected

132c94e31b8bca8ea921f9f96a57d684fa4ae0a9 → before f9b488641cfa63f9b41321530c543688b2e34f03

git versions

132c94e31b8bca8ea921f9f96a57d684fa4ae0a9 → before 91676705756af6a59a515087b8b854c8a28d12eb

git versions

132c94e31b8bca8ea921f9f96a57d684fa4ae0a9 → before 587d25c4b13d49c8fd05df2f71240f73bb2a058c

git versions

132c94e31b8bca8ea921f9f96a57d684fa4ae0a9 → before 5e8f3ac8fa3d411b422ad32b9168c46a4824cc79

git versions

132c94e31b8bca8ea921f9f96a57d684fa4ae0a9 → before b3ccde78f1608836e62320428abc0e8aa9cf2329

git versions

132c94e31b8bca8ea921f9f96a57d684fa4ae0a9 → before e01c79761c7b3373e80094c5eadb21cb864fa8bc

git versions

132c94e31b8bca8ea921f9f96a57d684fa4ae0a9 → before 6ab37fae14196ba2262b152a7d9222c50356d278

git versions

132c94e31b8bca8ea921f9f96a57d684fa4ae0a9 → before 33aadc7c72055fca93cb5a3691d836ebf8b31c9b

git versions

9c773201d61272db49f8f33a83a3cb2a3fe4b14f

git versions

3.8.6 → before 3.9

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

3.9

unaffected

0 → before 3.9

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

6.12.114 → 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: handle mount locking for automounts correctly

If mounts are propagated across user namespaces, attach_recursive_mnt() locks every copy of the source mount to protect overmounts from vanishing and revealing the underlying files or directories.

The user namespace is taken from the caller's mount namespaces since this is where the mounts end up. Except, that's not always true. Automounts may legitimately get popped in by tasks located in a different mount and user namespace during path lookup.

Then check doesn't make sense at that point. The copy in the namespace of the parent - which may be the host's - is now locked and the host cannot change the flags of its own mounts anymore.

Here's the reproducer:

  • host has debugfs mounted nosuid,nodev,noexec and shared

  • tracefs automount below it is not yet active

  • hand a child process a directory descriptor on that mount

  • child process enters auser and mount namespace

  • child process' namespace now holds a locked copy of the host's debugfs mount that receives propagation from it

  • child process stats "tracing/." through the descriptor

  • lookup runs on the host's mount so the automount lands below the host's mount

  • propagation puts a copy below the child's copy

  • both try to clear the flags on the mount they got, with a bind remount:

    host, on its own automount: MS_REMOUNT|MS_BIND = EPERM child, on the copy in its namespace: MS_REMOUNT|MS_BIND = 0

So the lock landed on the host's mount instead of the child's copy. Congrats. So we need to compare with the owner of the namespace the mount actually gets mounted on. For all regular cases that is the caller's mount namespace and so nothing changes.

Detached trees in anonymous mount namespaces by be handed over via SCM_RIGHTS or inherited in other ways on purpose so the attaching task's mount namespace is authoritative, not the creator of the detached tree.

References

8 sources
git.kernel.org/stable/c/f9b488641cfa63f9b41321530c543688b2e34f03
Source referenceLinux
git.kernel.org/stable/c/91676705756af6a59a515087b8b854c8a28d12eb
Source referenceLinux
git.kernel.org/stable/c/587d25c4b13d49c8fd05df2f71240f73bb2a058c
Source referenceLinux
git.kernel.org/stable/c/5e8f3ac8fa3d411b422ad32b9168c46a4824cc79
Source referenceLinux
git.kernel.org/stable/c/b3ccde78f1608836e62320428abc0e8aa9cf2329
Source referenceLinux
git.kernel.org/stable/c/e01c79761c7b3373e80094c5eadb21cb864fa8bc
Source referenceLinux
View 2 more references
git.kernel.org/stable/c/6ab37fae14196ba2262b152a7d9222c50356d278
Source referenceLinux
git.kernel.org/stable/c/33aadc7c72055fca93cb5a3691d836ebf8b31c9b
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-2026-98977

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): 3.9

Before: 5.10.273

Vulnerable product

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

From (inclusive): 3.9

Before: 5.15.224

Vulnerable product

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

From (inclusive): 3.9

Before: 6.1.191

Vulnerable product

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

From (inclusive): 3.9

Before: 6.6.160

Vulnerable product

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

From (inclusive): 3.9

Before: 6.12.114

Vulnerable product

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

From (inclusive): 3.9

Before: 6.18.57

Vulnerable product

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

From (inclusive): 3.9

Before: 7.2.11

Vulnerable product

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

From (inclusive): 3.9

Before: 7.3

Vulnerable product

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

From (inclusive): 3.8.6

Applicability preview
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]
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.

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