CVE-2025-39731

Local denial of service via interrupt-context unmapping

Published Sep 7, 2025 · Updated May 11, 2026

Invalid-context memory unmapping in affected Linux F2FS branches allows local users to disrupt service through compressed-file reads. The f2fs_read_end_io path checks in_task() but can synchronously call vm_unmap_ram() while interrupts are disabled, invoking a sleeping operation from an invalid context. Reachability requires low-privilege local access and an affected compressed-read path; the published trace shows a kernel warning but does not identify a specific crash mode.

CVSS severity5.5
Medium
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

Invalid-context memory unmapping in affected Linux F2FS branches allows local users to disrupt service through compressed-file reads. The f2fs_read_end_io path checks in_task() but can synchronously call vm_unmap_ram() while interrupts are disabled, invoking a sleeping operation from an invalid context. Reachability requires low-privilege local access and an affected compressed-read path; the published trace shows a kernel warning but does not identify a specific crash mode.

The record

CVE
CVE-2025-39731
Published
Sep 7, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 7, 2025CVE publishedPublication date reported by the CVE source.
  2. May 11, 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=6.0
  2. Affected versionversion=bff139b49d9f70c1ac5384aac94554846aa834de <08a7efc5b02a0620ae16aa9584060e980a69cb55
  3. Affected versionversion=bff139b49d9f70c1ac5384aac94554846aa834de <0fe7976b62546f1e95eebfe9879925e9aa22b7a8
  4. Affected versionversion=bff139b49d9f70c1ac5384aac94554846aa834de <1023836d1b9465593c8746f97d608da32958785f
  5. Affected versionversion=bff139b49d9f70c1ac5384aac94554846aa834de <18eea36f4f460ead3750ed4afe5496f7ce55f99e
  6. Affected versionversion=bff139b49d9f70c1ac5384aac94554846aa834de <411e00f44e2e1a7fdb526013b25a7f0ed22a0947
  7. Affected versionversion=bff139b49d9f70c1ac5384aac94554846aa834de <eb69e69a5ae6c8350957893b5f68bd55b1565fb2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.0; version=bff139b49d9f70c1ac5384aac94554846aa834de <08a7efc5b02a0620ae16aa9584060e980a69cb55; version=bff139b49d9f70c1ac5384aac94554846aa834de <0fe7976b62546f1e95eebfe9879925e9aa22b7a8; version=bff139b49d9f70c1ac5384aac94554846aa834de <1023836d1b9465593c8746f97d608da32958785f; version=bff139b49d9f70c1ac5384aac94554846aa834de <18eea36f4f460ead3750ed4afe5496f7ce55f99e; version=bff139b49d9f70c1ac5384aac94554846aa834de <411e00f44e2e1a7fdb526013b25a7f0ed22a0947; version=bff139b49d9f70c1ac5384aac94554846aa834de <eb69e69a5ae6c8350957893b5f68bd55b1565fb2

Published CVSS scores

5.5CanonicalCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5NISTCVSS: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.

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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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