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CVE-2026-99040

KEYS: Fix add_key() race with keyring restriction

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, 21:25:33 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

8 ranges
Linux version evidence

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

affected

5ac7eace2d00eab5ae0e9fdee63e38aee6001f7c → before 24806fc9bca28fa1433bf938d1424dcb45d80e50

git versions

5ac7eace2d00eab5ae0e9fdee63e38aee6001f7c → before 9a5c2700336878465a630804a2d21864f22eca9c

git versions

5ac7eace2d00eab5ae0e9fdee63e38aee6001f7c → before b3e404550dc2b7f3d4bb64b1da8005a1fa9a798d

git versions

5ac7eace2d00eab5ae0e9fdee63e38aee6001f7c → before 305f1828b871dd46bf41addeb6f11d2c162dcb25

git versions

5ac7eace2d00eab5ae0e9fdee63e38aee6001f7c → before f99399b48e3edd6851fac34cd329bab9f1f33baf

git versions

5ac7eace2d00eab5ae0e9fdee63e38aee6001f7c → before 11516a0c402a6c1fa52254aa70d8d65fb921e59e

git versions

5ac7eace2d00eab5ae0e9fdee63e38aee6001f7c → before da0b595d8e6e2dd798f6e34e09dc51a13b888514

git versions

5ac7eace2d00eab5ae0e9fdee63e38aee6001f7c → before dd3ea3fcba7c75493760cdbccd35f029597e8d5e

git 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

4.7

unaffected

0 → before 4.7

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:

KEYS: Fix add_key() race with keyring restriction

__key_create_or_update() snapshots keyring->restrict_link before taking the destination keyring's semaphore. keyring_restrict() installs a restriction while holding that semaphore.

This allows a writer to observe no restriction, wait for the keyring owner to install a reject-all restriction and return successfully, and then link a key using the stale NULL snapshot. The writer only needs write permission on the destination keyring.

Move the restrict_link read after __key_link_lock() and __key_link_begin(). The read and the subsequent restriction check are then serialized with restriction installation by keyring->sem.

The race was reproduced on v7.2.8 in 19 executions where restriction installation returned before the link completed. All 19 linked the key despite the reject-all restriction. With this change, 312 executions reached the same ordering and every add_key() call failed with -EPERM.

The issue was found by manual concurrency analysis assisted by AI-based analysis and independently verified with a QEMU reproducer and kernel instrumentation.

References

8 sources
git.kernel.org/stable/c/24806fc9bca28fa1433bf938d1424dcb45d80e50
Source referenceLinux
git.kernel.org/stable/c/9a5c2700336878465a630804a2d21864f22eca9c
Source referenceLinux
git.kernel.org/stable/c/b3e404550dc2b7f3d4bb64b1da8005a1fa9a798d
Source referenceLinux
git.kernel.org/stable/c/305f1828b871dd46bf41addeb6f11d2c162dcb25
Source referenceLinux
git.kernel.org/stable/c/f99399b48e3edd6851fac34cd329bab9f1f33baf
Source referenceLinux
git.kernel.org/stable/c/11516a0c402a6c1fa52254aa70d8d65fb921e59e
Source referenceLinux
View 2 more references
git.kernel.org/stable/c/da0b595d8e6e2dd798f6e34e09dc51a13b888514
Source referenceLinux
git.kernel.org/stable/c/dd3ea3fcba7c75493760cdbccd35f029597e8d5e
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-2026-99040

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): 4.7

Before: 5.10.273

Vulnerable product

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

From (inclusive): 4.7

Before: 5.15.224

Vulnerable product

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

From (inclusive): 4.7

Before: 6.1.191

Vulnerable product

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

From (inclusive): 4.7

Before: 6.6.160

Vulnerable product

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

From (inclusive): 4.7

Before: 6.12.113

Vulnerable product

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

From (inclusive): 4.7

Before: 6.18.57

Vulnerable product

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

From (inclusive): 4.7

Before: 7.2.11

Vulnerable product

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

From (inclusive): 4.7

Before: 7.3

Applicability preview
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    "nodes": [
      {
        "operator": "OR",
        "negate": false,
        "cpeMatch": [
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "4.7",
            "versionEndExcluding": "5.10.273"
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          {
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          {
            "vulnerable": true,
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            "versionStartIncluding": "4.7",
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          {
            "vulnerable": true,
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          {
            "vulnerable": true,
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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.

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