CVE-2026-31666

Extent-tree corruption via false lookup success

Published Apr 24, 2026 · Updated Apr 24, 2026

Incorrect error handling in affected Linux Kernel releases allows local users to corrupt the btrfs extent tree through a failed data-reference lookup. After btrfs_next_leaf() succeeds, lookup_extent_data_ref() overwrites -ENOENT with zero and reports success when the next leaf's first key has a different object ID or type. The caller then operates on the wrong extent-tree item; reaching the flaw requires local low-privileged access and a btrfs filesystem.

CVSS severity7.8
High
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect error handling in affected Linux Kernel releases allows local users to corrupt the btrfs extent tree through a failed data-reference lookup. After btrfs_next_leaf() succeeds, lookup_extent_data_ref() overwrites -ENOENT with zero and reports success when the next leaf's first key has a different object ID or type. The caller then operates on the wrong extent-tree item; reaching the flaw requires local low-privileged access and a btrfs filesystem.

The record

CVE
CVE-2026-31666
Published
Apr 24, 2026
Updated
Apr 24, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
Unavailable
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 24, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1618aa3c2e0163f5ac34d514ae89474521910536 <316fb1b3169efb081d2db910cbbfef445afa03b9
  2. Affected versionversion=1618aa3c2e0163f5ac34d514ae89474521910536 <4125a194db4a6cf91f619f38788272651cb97dce
  3. Affected versionversion=1618aa3c2e0163f5ac34d514ae89474521910536 <450e6a685d0cad95b15f8af152057bd0bf79f50b
  4. Affected versionversion=1618aa3c2e0163f5ac34d514ae89474521910536 <ab1e022379c3c811aa72da8eb0c7507859a1d0f5
  5. Affected versionversion=6.10

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1618aa3c2e0163f5ac34d514ae89474521910536 <316fb1b3169efb081d2db910cbbfef445afa03b9; version=1618aa3c2e0163f5ac34d514ae89474521910536 <4125a194db4a6cf91f619f38788272651cb97dce; version=1618aa3c2e0163f5ac34d514ae89474521910536 <450e6a685d0cad95b15f8af152057bd0bf79f50b; version=1618aa3c2e0163f5ac34d514ae89474521910536 <ab1e022379c3c811aa72da8eb0c7507859a1d0f5; version=6.10

Published CVSS scores

7.8kernel.orgCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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