CVE-2025-38430Network attack vector

Unauthenticated file access via mis-typed request state

Published Jul 25, 2025 · Updated Aug 5, 2026

Type confusion in Linux nfsd 4.8 and later allows remote attackers to access Kerberos-protected NFS exports via crafted RPCs. nfsd4_spo_must_allow() treats response storage for non-NFSv4 RPC procedures as NFSv4 compound state, reading stale or out-of-bounds fields and writing through the mis-typed structure. An exposed NFS server with security-flavor restrictions is sufficient; crafted NFSv3, NFSACL, or NLM requests can bypass export authentication, read or write files, corrupt response state, or crash kernel service threads.

CVSS severity9.8
Critical
EPSS probability0.50%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Type confusion in Linux nfsd 4.8 and later allows remote attackers to access Kerberos-protected NFS exports via crafted RPCs. nfsd4_spo_must_allow() treats response storage for non-NFSv4 RPC procedures as NFSv4 compound state, reading stale or out-of-bounds fields and writing through the mis-typed structure. An exposed NFS server with security-flavor restrictions is sufficient; crafted NFSv3, NFSACL, or NLM requests can bypass export authentication, read or write files, corrupt response state, or crash kernel service threads.

The record

CVE
CVE-2025-38430
Published
Jul 25, 2025
Updated
Aug 5, 2026
Vendor
Siemens
Product
SIPLUS S7-1500 CPU 1518-4 PN/DP MFP
Classifications
CWE-20, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 25, 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=V3.1.5 <*

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Siemens · SIPLUS S7-1500 CPU 1518-4 PN/DP MFPversion=V3.1.5 <*
The Linux Kernel Organization · Linuxversion=4.8; version=ed94164398c935a42be7b129a478eb19c598b68a <1244f0b2c3cecd3f349a877006e67c9492b41807; version=ed94164398c935a42be7b129a478eb19c598b68a <2c54bd5a380ebf646fb9efbc4ae782ff3a83a5af; version=ed94164398c935a42be7b129a478eb19c598b68a <425efc6b3292a3c79bfee4a1661cf043dcd9cf2f; version=ed94164398c935a42be7b129a478eb19c598b68a <64a723b0281ecaa59d31aad73ef8e408a84cb603; version=ed94164398c935a42be7b129a478eb19c598b68a <7a75a956692aa64211a9e95781af1ec461642de4; version=ed94164398c935a42be7b129a478eb19c598b68a <b1d0323a09a29f81572c7391e0d80d78724729c9; version=ed94164398c935a42be7b129a478eb19c598b68a <bf78a2706ce975981eb5167f2d3b609eb5d24c19; version=ed94164398c935a42be7b129a478eb19c598b68a <e7e943ddd1c6731812357a28e7954ade3a7d8517
Siemens · SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPversion=V3.1.5 <*
Siemens · SIMATIC S7-1500 CPU 1518-4 PN/DP MFPversion=V3.1.5 <*

Published CVSS scores

9.8Linux kernel CVE teamCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
5.5Siemens ProductCERTCVSS: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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
T1190Exploit Public-Facing Application

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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