CVE-2025-40326Network attack vector

Remote NFS service crash via missing GETATTR handlers

Published Dec 8, 2025 · Updated Aug 5, 2026

Denial of service in Linux kernel NFSD allows remote attackers to crash the NFS server via crafted NFSv4 GETATTR requests. The encoder table in fs/nfsd/nfs4xdr.c leaves FATTR4_TIME_DELEG_ACCESS and FATTR4_TIME_DELEG_MODIFY without handlers, so either bit invokes a NULL function pointer instead of rejecting the invalid attribute. An unauthenticated network peer can reach the path against an exported NFSv4 server; repeated requests can terminate NFSD threads or panic the host when panic_on_oops is enabled.

CVSS severity7.5
High
EPSS probability0.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Linux kernel NFSD allows remote attackers to crash the NFS server via crafted NFSv4 GETATTR requests. The encoder table in fs/nfsd/nfs4xdr.c leaves FATTR4_TIME_DELEG_ACCESS and FATTR4_TIME_DELEG_MODIFY without handlers, so either bit invokes a NULL function pointer instead of rejecting the invalid attribute. An unauthenticated network peer can reach the path against an exported NFSv4 server; repeated requests can terminate NFSD threads or panic the host when panic_on_oops is enabled.

The record

CVE
CVE-2025-40326
Published
Dec 8, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 8, 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

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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=51c0d4f7e317d3cb4a3001e502bd8ca2d57f2a4b <4f76435fd517981f01608678c06ad9718a86ee98
  2. Affected versionversion=51c0d4f7e317d3cb4a3001e502bd8ca2d57f2a4b <d8f3f94dc950e7c62c96af432c26745885b0a18a
  3. Affected versionversion=6.14

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=51c0d4f7e317d3cb4a3001e502bd8ca2d57f2a4b <4f76435fd517981f01608678c06ad9718a86ee98; version=51c0d4f7e317d3cb4a3001e502bd8ca2d57f2a4b <d8f3f94dc950e7c62c96af432c26745885b0a18a; version=6.14

Published CVSS scores

7.5Linux kernel CVE teamCVSS:3.1/AV:N/AC:L/PR:N/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

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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