CVE-2025-39791

Filesystem corruption via partial zoned-write BIO acceptance

Published Sep 11, 2025 · Updated Aug 5, 2026

Improper write handling in Linux dm-crypt allows local users to corrupt XFS or Btrfs data through large writes to zoned targets. crypt_map partially accepts write BIOs that exceed max_write_size, causing chained zone-append emulation to return the original BIO sector and allowing split remainders to re-enter a frozen queue. Exploitation requires write access to XFS or Btrfs on a zoned dm-crypt target; outcomes are filesystem corruption or a queue-freeze deadlock, while regular dm-crypt devices are unaffected.

CVSS severity7.8
High
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper write handling in Linux dm-crypt allows local users to corrupt XFS or Btrfs data through large writes to zoned targets. crypt_map partially accepts write BIOs that exceed max_write_size, causing chained zone-append emulation to return the original BIO sector and allowing split remainders to re-enter a frozen queue. Exploitation requires write access to XFS or Btrfs on a zoned dm-crypt target; outcomes are filesystem corruption or a queue-freeze deadlock, while regular dm-crypt devices are unaffected.

The record

CVE
CVE-2025-39791
Published
Sep 11, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-667, T1499, T1485
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 11, 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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=6.10
  2. Affected versionversion=f211268ed1f9bdf48f06a3ead5f5d88437450579 <52a2c4c60470352acf9cde7a2dfa661c1e67e796
  3. Affected versionversion=f211268ed1f9bdf48f06a3ead5f5d88437450579 <8864616719b6bbf92356bc89ff544b0cd484c656
  4. Affected versionversion=f211268ed1f9bdf48f06a3ead5f5d88437450579 <e549663849e5bb3b985dc2d293069f0d9747ae72

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.10; version=f211268ed1f9bdf48f06a3ead5f5d88437450579 <52a2c4c60470352acf9cde7a2dfa661c1e67e796; version=f211268ed1f9bdf48f06a3ead5f5d88437450579 <8864616719b6bbf92356bc89ff544b0cd484c656; version=f211268ed1f9bdf48f06a3ead5f5d88437450579 <e549663849e5bb3b985dc2d293069f0d9747ae72

Published CVSS scores

7.8kernel.orgCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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.

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

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

CWE-667Improper Locking
T1499Endpoint Denial of Service
T1485Data Destruction

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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