CVE-2026-89696Network attack vector

Remote nfsd crash via foreign-filehandle operation

Published Sep 11, 2026 · Updated Sep 11, 2026

NULL pointer dereference in Linux 5.6 and affected kernel commits allows remote attackers to crash an nfsd thread via NFSv4.2. After a foreign PUTFH returns success with NULL filehandle members, the compound dispatcher permits SETATTR to dereference fh_export before SAVEFH. Exploitation requires CONFIG_NFSD_V4_2_INTER_SSC and a crafted inter-server COPY compound; the demonstrated consequence is an nfsd thread crash.

CVSS severityUnavailable
Unscored
EPSS probability0.76%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in Linux 5.6 and affected kernel commits allows remote attackers to crash an nfsd thread via NFSv4.2. After a foreign PUTFH returns success with NULL filehandle members, the compound dispatcher permits SETATTR to dereference fh_export before SAVEFH. Exploitation requires CONFIG_NFSD_V4_2_INTER_SSC and a crafted inter-server COPY compound; the demonstrated consequence is an nfsd thread crash.

The record

CVE
CVE-2026-89696
Published
Sep 11, 2026
Updated
Sep 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 11, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 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=5.6
  2. Affected versionversion=b9e8638e3d9ed8334f1f7071e081860aac37e83e <311f7d926630940650447cbd1c932b076b40a6c4
  3. Affected versionversion=b9e8638e3d9ed8334f1f7071e081860aac37e83e <35f248bd40b47b229d4999581df45b97daadd977
  4. Affected versionversion=b9e8638e3d9ed8334f1f7071e081860aac37e83e <bf4d338dc8625d70c7f2cb0657d66851a7ac9154
  5. Affected versionversion=b9e8638e3d9ed8334f1f7071e081860aac37e83e <c59738a00aa51b16adc1b5ceb7c80877168efb4d

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.6; version=b9e8638e3d9ed8334f1f7071e081860aac37e83e <311f7d926630940650447cbd1c932b076b40a6c4; version=b9e8638e3d9ed8334f1f7071e081860aac37e83e <35f248bd40b47b229d4999581df45b97daadd977; version=b9e8638e3d9ed8334f1f7071e081860aac37e83e <bf4d338dc8625d70c7f2cb0657d66851a7ac9154; version=b9e8638e3d9ed8334f1f7071e081860aac37e83e <c59738a00aa51b16adc1b5ceb7c80877168efb4d

Published CVSS scores

No CVSS assessment is available in this record.

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)
Vectornetwork
Privilegesunauthenticated
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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