CVE-2025-38338

System hang via NFS folio double-unlock

Published Jul 10, 2025 · Updated May 11, 2026

Deadlock in the Linux kernel NFS read path allows local users to hang processes by racing a file read with truncation from another client. The nfs_return_empty_folio() path calls folio_unlock() without the required nfs_netfs_folio_unlock() guard when fscache is enabled, toggling PG_locked back on. Exploitation requires fscache and precisely timed activity from another NFS client; affected processes wait indefinitely in folio_wait_bit_common().

CVSS severity5.5
Medium
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Deadlock in the Linux kernel NFS read path allows local users to hang processes by racing a file read with truncation from another client. The nfs_return_empty_folio() path calls folio_unlock() without the required nfs_netfs_folio_unlock() guard when fscache is enabled, toggling PG_locked back on. Exploitation requires fscache and precisely timed activity from another NFS client; affected processes wait indefinitely in folio_wait_bit_common().

The record

CVE
CVE-2025-38338
Published
Jul 10, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-833, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 10, 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=000dbe0bec058cbf2ca9e156e4a5584f5158b0f9 <14f5549ad163be2c018abc1bb38370fff617a243
  2. Affected versionversion=000dbe0bec058cbf2ca9e156e4a5584f5158b0f9 <1e93b61d3eaa14bfebcc2716ac09d43f3845d420
  3. Affected versionversion=000dbe0bec058cbf2ca9e156e4a5584f5158b0f9 <4c10fa44bc5f700e2ea21de2fbae520ba21f19d9
  4. Affected versionversion=000dbe0bec058cbf2ca9e156e4a5584f5158b0f9 <5bf0b9eeb0174686f22c2e5b8fb9f47ad25da6f5
  5. Affected versionversion=6.4

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=000dbe0bec058cbf2ca9e156e4a5584f5158b0f9 <14f5549ad163be2c018abc1bb38370fff617a243; version=000dbe0bec058cbf2ca9e156e4a5584f5158b0f9 <1e93b61d3eaa14bfebcc2716ac09d43f3845d420; version=000dbe0bec058cbf2ca9e156e4a5584f5158b0f9 <4c10fa44bc5f700e2ea21de2fbae520ba21f19d9; version=000dbe0bec058cbf2ca9e156e4a5584f5158b0f9 <5bf0b9eeb0174686f22c2e5b8fb9f47ad25da6f5; version=6.4

Published CVSS scores

7.8NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
5.5Red HatCVSS: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

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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

CWE-833Deadlock
T1499.004Application or System Exploitation

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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