CVE-2026-89684Network attack vector

NFS server crash via cpntf publication race

Published Sep 11, 2026 · Updated Sep 11, 2026

Race condition in the Linux kernel NFS server allows remote authenticated users to crash the host through concurrent NFSv4.2 requests. nfs4_alloc_init_cpntf_state publishes a copy-notify entry in the state-ID registry before linking its zeroed cp_list into the parent list. An authenticated NFSv4.2 client can race COPY_NOTIFY with OFFLOAD_CANCEL, causing list_del to dereference the zeroed list head and oops the server.

CVSS severityUnavailable
Unscored
EPSS probability0.51%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Race condition in the Linux kernel NFS server allows remote authenticated users to crash the host through concurrent NFSv4.2 requests. nfs4_alloc_init_cpntf_state publishes a copy-notify entry in the state-ID registry before linking its zeroed cp_list into the parent list. An authenticated NFSv4.2 client can race COPY_NOTIFY with OFFLOAD_CANCEL, causing list_del to dereference the zeroed list head and oops the server.

The record

CVE
CVE-2026-89684
Published
Sep 11, 2026
Updated
Sep 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
network
Privileges
authenticated

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=624322f1adc58acd0b69f77a6ddc764207e97241 <21d6c5957f5ca97d7352e60f55ea412beb9419f5
  3. Affected versionversion=624322f1adc58acd0b69f77a6ddc764207e97241 <a631a26a8777bb235eabd478bbbaf26a4db750bf
  4. Affected versionversion=624322f1adc58acd0b69f77a6ddc764207e97241 <be3a5c1d857b0dcbc11796cea603ef25834f75b2
  5. Affected versionversion=624322f1adc58acd0b69f77a6ddc764207e97241 <c7270f62e7a05a2ee68aa2b74262b658a14463bd

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.6; version=624322f1adc58acd0b69f77a6ddc764207e97241 <21d6c5957f5ca97d7352e60f55ea412beb9419f5; version=624322f1adc58acd0b69f77a6ddc764207e97241 <a631a26a8777bb235eabd478bbbaf26a4db750bf; version=624322f1adc58acd0b69f77a6ddc764207e97241 <be3a5c1d857b0dcbc11796cea603ef25834f75b2; version=624322f1adc58acd0b69f77a6ddc764207e97241 <c7270f62e7a05a2ee68aa2b74262b658a14463bd

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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
Privilegesauthenticated
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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