CVE-2025-40303

Kernel crash via dirty metadata writeback

Published Dec 8, 2025 · Updated Aug 5, 2026

Use-after-free in the Linux btrfs filesystem allows local users to crash the kernel during unmount of RAID56 metadata volumes. After an error freezes transactions, close_ctree() calls iput() on the btree inode, writing dirty metadata through an rmw_workers queue that has already been stopped and freed. Reachability requires local write access, an error-state btrfs volume with pending dirty metadata, RAID5 or RAID6 metadata, and subsequent unmount; the writeback can also corrupt filesystem metadata.

CVSS severity7.8
High
EPSS probability0.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in the Linux btrfs filesystem allows local users to crash the kernel during unmount of RAID56 metadata volumes. After an error freezes transactions, close_ctree() calls iput() on the btree inode, writing dirty metadata through an rmw_workers queue that has already been stopped and freed. Reachability requires local write access, an error-state btrfs volume with pending dirty metadata, RAID5 or RAID6 metadata, and subsequent unmount; the writeback can also corrupt filesystem metadata.

The record

CVE
CVE-2025-40303
Published
Dec 8, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 8, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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=13e6c37b989859e70b0d73d3f2cb0aa022159b17 <066ee13f05fbd82ada01883e51f0695172f98dff
  2. Affected versionversion=13e6c37b989859e70b0d73d3f2cb0aa022159b17 <2618849f31e7cf51fadd4a5242458501a6d5b315
  3. Affected versionversion=13e6c37b989859e70b0d73d3f2cb0aa022159b17 <54a5b5a15588e3b0b294df31474d08a2678d4291
  4. Affected versionversion=13e6c37b989859e70b0d73d3f2cb0aa022159b17 <e2b3859067bf012d53c49b3f885fef40624a2c83
  5. Affected versionversion=3.10

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=13e6c37b989859e70b0d73d3f2cb0aa022159b17 <066ee13f05fbd82ada01883e51f0695172f98dff; version=13e6c37b989859e70b0d73d3f2cb0aa022159b17 <2618849f31e7cf51fadd4a5242458501a6d5b315; version=13e6c37b989859e70b0d73d3f2cb0aa022159b17 <54a5b5a15588e3b0b294df31474d08a2678d4291; version=13e6c37b989859e70b0d73d3f2cb0aa022159b17 <e2b3859067bf012d53c49b3f885fef40624a2c83; version=3.10

Published CVSS scores

7.8Linux Kernel CVE TeamCVSS: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

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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

T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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