CVE-2026-23181

Kernel crash via unsynchronized btrfs block-size change

Published Feb 14, 2026 · Updated Feb 14, 2026

Race condition in Linux Kernel 6.15 through 6.18.9 allows local users to crash the kernel while mounting a btrfs device. do_read_cache_folio allocates an order-0 folio before BLKBSZSET raises the device block size and mapping minimum folio order, so filemap_add_folio asserts or create_empty_buffers dereferences null. Exploitation requires local access able to change the block-device size and mount the btrfs device; the bounded consequence is a kernel crash.

CVSS severityUnavailable
Unscored
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Race condition in Linux Kernel 6.15 through 6.18.9 allows local users to crash the kernel while mounting a btrfs device. do_read_cache_folio allocates an order-0 folio before BLKBSZSET raises the device block size and mapping minimum folio order, so filemap_add_folio asserts or create_empty_buffers dereferences null. Exploitation requires local access able to change the block-device size and mount the btrfs device; the bounded consequence is a kernel crash.

The record

CVE
CVE-2026-23181
Published
Feb 14, 2026
Updated
Feb 14, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 14, 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=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <3f29d661e5686f3aa14e6f11537ff5c49846f2e2
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ccb3c75d57039adb3170ae54a0d470e359705984

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <3f29d661e5686f3aa14e6f11537ff5c49846f2e2; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ccb3c75d57039adb3170ae54a0d470e359705984

Published CVSS scores

No CVSS assessment is available in this record.

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service

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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