CVE-2025-39730

Out-of-bounds read via short NFS filehandle

Published Sep 7, 2025 · Updated Jun 11, 2026

Out-of-bounds access in the Linux kernel NFS export handler allows local users to read beyond supplied data via a malformed filehandle. In nfs_fh_to_dentry(), fs/nfs/export.c reads server_fh->size before checking that fh_len covers the embedded structure, so a short handle drives an out-of-bounds read. Exploitation requires local low-privileged access to the NFS export decoding path; public sources document no demonstrated crash, code execution, or broader compromise.

CVSS severity7.8
High
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

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Summary

What happened

Out-of-bounds access in the Linux kernel NFS export handler allows local users to read beyond supplied data via a malformed filehandle. In nfs_fh_to_dentry(), fs/nfs/export.c reads server_fh->size before checking that fh_len covers the embedded structure, so a short handle drives an out-of-bounds read. Exploitation requires local low-privileged access to the NFS export decoding path; public sources document no demonstrated crash, code execution, or broader compromise.

The record

CVE
CVE-2025-39730
Published
Sep 7, 2025
Updated
Jun 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 7, 2025CVE publishedPublication date reported by the CVE source.
  2. Jun 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=20fa19027286983ab2734b5910c4a687436e0c31 <12ad3def2e5e0b120e3d0cb6ce8b7b796819ad40
  2. Affected versionversion=20fa19027286983ab2734b5910c4a687436e0c31 <2ad40b7992aa26bc631afc1a995b0e3ddc30de3f
  3. Affected versionversion=20fa19027286983ab2734b5910c4a687436e0c31 <3570ef5c31314c13274c935a20b91768ab5bf412
  4. Affected versionversion=20fa19027286983ab2734b5910c4a687436e0c31 <763810bb883cb4de412a72f338d80947d97df67b
  5. Affected versionversion=20fa19027286983ab2734b5910c4a687436e0c31 <7dd36f7477d1e03a1fcf8d13531ca326c4fb599f
  6. Affected versionversion=20fa19027286983ab2734b5910c4a687436e0c31 <7f8eca87fef7519e9c41f3258f25ebc2752247ee
  7. Affected versionversion=20fa19027286983ab2734b5910c4a687436e0c31 <b7f7866932466332a2528fda099000b035303485
  8. Affected versionversion=20fa19027286983ab2734b5910c4a687436e0c31 <cb09afa0948d96b1e385d609ed044bb1aa043536
  9. Affected versionversion=20fa19027286983ab2734b5910c4a687436e0c31 <ef93a685e01a281b5e2a25ce4e3428cf9371a205
  10. Affected versionversion=4.13

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=20fa19027286983ab2734b5910c4a687436e0c31 <12ad3def2e5e0b120e3d0cb6ce8b7b796819ad40; version=20fa19027286983ab2734b5910c4a687436e0c31 <2ad40b7992aa26bc631afc1a995b0e3ddc30de3f; version=20fa19027286983ab2734b5910c4a687436e0c31 <3570ef5c31314c13274c935a20b91768ab5bf412; version=20fa19027286983ab2734b5910c4a687436e0c31 <763810bb883cb4de412a72f338d80947d97df67b; version=20fa19027286983ab2734b5910c4a687436e0c31 <7dd36f7477d1e03a1fcf8d13531ca326c4fb599f; version=20fa19027286983ab2734b5910c4a687436e0c31 <7f8eca87fef7519e9c41f3258f25ebc2752247ee; version=20fa19027286983ab2734b5910c4a687436e0c31 <b7f7866932466332a2528fda099000b035303485; version=20fa19027286983ab2734b5910c4a687436e0c31 <cb09afa0948d96b1e385d609ed044bb1aa043536; version=20fa19027286983ab2734b5910c4a687436e0c31 <ef93a685e01a281b5e2a25ce4e3428cf9371a205; version=4.13

Published CVSS scores

7.8NIST NVDCVSS: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

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 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

No sourced classifications are available.

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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