CVE-2025-39885

Filesystem hang via recursive FIEMAP locking

Published Sep 23, 2025 · Updated Sep 23, 2025

Improper locking in Linux OCFS2 2.6.28 and later affected branches allows local users to hang the filesystem through a crafted FIEMAP request. ocfs2_fiemap() holds ip_alloc_sem for reading while copying extent data to a user buffer; a page fault enters ocfs2_page_mkwrite() and recursively requests the same semaphore for writing. The user must locally issue FS_IOC_FIEMAP against the extent list of a specially crafted memory-mapped OCFS2 file, and the resulting deadlock interrupts filesystem service.

CVSS severity5.5
Medium
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

Improper locking in Linux OCFS2 2.6.28 and later affected branches allows local users to hang the filesystem through a crafted FIEMAP request. ocfs2_fiemap() holds ip_alloc_sem for reading while copying extent data to a user buffer; a page fault enters ocfs2_page_mkwrite() and recursively requests the same semaphore for writing. The user must locally issue FS_IOC_FIEMAP against the extent list of a specially crafted memory-mapped OCFS2 file, and the resulting deadlock interrupts filesystem service.

The record

CVE
CVE-2025-39885
Published
Sep 23, 2025
Updated
Sep 23, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-667, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 23, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 23, 2025Record 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=00dc417fa3e763345b34ccb6034d72de76eea0a1 <04100f775c2ea501927f508f17ad824ad1f23c8d
  2. Affected versionversion=00dc417fa3e763345b34ccb6034d72de76eea0a1 <0709bc11b942870fc0a7be150e42aea42321093a
  3. Affected versionversion=00dc417fa3e763345b34ccb6034d72de76eea0a1 <1d3c96547ee2ddeaddf8f19a3ef99ea06cc8115e
  4. Affected versionversion=00dc417fa3e763345b34ccb6034d72de76eea0a1 <36054554772f95d090eb45793faf6aa3c0254b02
  5. Affected versionversion=00dc417fa3e763345b34ccb6034d72de76eea0a1 <9efcb7a8b97310efed995397941a292cf89fa94f
  6. Affected versionversion=2.6.28

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=00dc417fa3e763345b34ccb6034d72de76eea0a1 <04100f775c2ea501927f508f17ad824ad1f23c8d; version=00dc417fa3e763345b34ccb6034d72de76eea0a1 <0709bc11b942870fc0a7be150e42aea42321093a; version=00dc417fa3e763345b34ccb6034d72de76eea0a1 <1d3c96547ee2ddeaddf8f19a3ef99ea06cc8115e; version=00dc417fa3e763345b34ccb6034d72de76eea0a1 <36054554772f95d090eb45793faf6aa3c0254b02; version=00dc417fa3e763345b34ccb6034d72de76eea0a1 <9efcb7a8b97310efed995397941a292cf89fa94f; version=2.6.28

Published CVSS scores

5.5NIST National Vulnerability DatabaseCVSS: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

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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