CVE-2026-93255

Spurious btrfs warning via extent-buffer race

Published Sep 24, 2026 · Updated Sep 24, 2026

Race condition in Linux btrfs 7.1.8 through 7.2 allows local users with mount privileges to trigger a spurious kernel warning. The read-completion path clears EXTENT_BUFFER_READING before dropping its extra reference, so invalidation can inspect a transient reference count. Reaching the race requires concurrent metadata-read completion and filesystem invalidation; the published report identifies a false alert, not data loss or service interruption.

CVSS severityUnavailable
Unscored
EPSS probability0.20%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Race condition in Linux btrfs 7.1.8 through 7.2 allows local users with mount privileges to trigger a spurious kernel warning. The read-completion path clears EXTENT_BUFFER_READING before dropping its extra reference, so invalidation can inspect a transient reference count. Reaching the race requires concurrent metadata-read completion and filesystem invalidation; the published report identifies a false alert, not data loss or service interruption.

The record

CVE
CVE-2026-93255
Published
Sep 24, 2026
Updated
Sep 24, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Sep 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 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=7.1.8 <7.2
  2. Affected versionversion=7.2
  3. Affected versionversion=83f7e52b7ed1c3e03b79123e20b6f6adf8d886bb <2073f3d97b0c5d34fe64812d1237e37bd79c17ec
  4. Affected versionversion=83f7e52b7ed1c3e03b79123e20b6f6adf8d886bb <690c2accacb1aca91ab8186d15dee56da8723f31
  5. Affected versionversion=b0c33c0628c5b0678fcae2e05e7b2764149248f8

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linuxversion=7.1.8 <7.2; version=7.2; version=83f7e52b7ed1c3e03b79123e20b6f6adf8d886bb <2073f3d97b0c5d34fe64812d1237e37bd79c17ec; version=83f7e52b7ed1c3e03b79123e20b6f6adf8d886bb <690c2accacb1aca91ab8186d15dee56da8723f31; version=b0c33c0628c5b0678fcae2e05e7b2764149248f8

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.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
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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