CVE-2026-89662Network attack vector

NFS server crash via lock-owner teardown race

Published Sep 11, 2026 · Updated Sep 11, 2026

Use-after-free in Linux NFSD client teardown allows remote attackers to crash an NFS server through a blocked-lock teardown race. __destroy_client() walks a lock owner without holding a reference while the per-network laundromat can free that owner, causing a NULL dereference in remove_blocked_locks(). Exploitation requires an NFSv4 client to leave an owner referenced only by a blocked lock, invoke DESTROY_CLIENTID, and win the concurrent cleanup race.

CVSS severityUnavailable
Unscored
EPSS probability0.68%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Linux NFSD client teardown allows remote attackers to crash an NFS server through a blocked-lock teardown race. __destroy_client() walks a lock owner without holding a reference while the per-network laundromat can free that owner, causing a NULL dereference in remove_blocked_locks(). Exploitation requires an NFSv4 client to leave an owner referenced only by a blocked lock, invoke DESTROY_CLIENTID, and win the concurrent cleanup race.

The record

CVE
CVE-2026-89662
Published
Sep 11, 2026
Updated
Sep 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
network
Privileges
Unavailable

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=0f44e9da465ea259b6c9f31a627f3c50a16e1679
  2. Affected versionversion=4.14.31 <4.15
  3. Affected versionversion=4.15.14 <4.16
  4. Affected versionversion=4.16
  5. Affected versionversion=4.9.91 <4.10
  6. Affected versionversion=68ef3bc3166468678d5e1fdd216628c35bd1186f <4804c58f73a80d12df1de323bf97a164f6ee8743
  7. Affected versionversion=68ef3bc3166468678d5e1fdd216628c35bd1186f <5e2fa29d223a9a1e6a948e40b109d09081d1decd
  8. Affected versionversion=68ef3bc3166468678d5e1fdd216628c35bd1186f <8cf4ff0a7c083dd5e0067f517d63979b74b66649
  9. Affected versionversion=68ef3bc3166468678d5e1fdd216628c35bd1186f <a6ead6fff3a7d03e49845f048f7000a2e0d34431
  10. Affected versionversion=797bfd05d4040fbf766198b3cfcc1838002cc890
  11. Affected versionversion=e294c4c2d33b7307a89cdf31bec08a112d6a9297

What conditions does exploitation require?

Attack vectornetwork
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=0f44e9da465ea259b6c9f31a627f3c50a16e1679; version=4.14.31 <4.15; version=4.15.14 <4.16; version=4.16; version=4.9.91 <4.10; version=68ef3bc3166468678d5e1fdd216628c35bd1186f <4804c58f73a80d12df1de323bf97a164f6ee8743; version=68ef3bc3166468678d5e1fdd216628c35bd1186f <5e2fa29d223a9a1e6a948e40b109d09081d1decd; version=68ef3bc3166468678d5e1fdd216628c35bd1186f <8cf4ff0a7c083dd5e0067f517d63979b74b66649; version=68ef3bc3166468678d5e1fdd216628c35bd1186f <a6ead6fff3a7d03e49845f048f7000a2e0d34431; version=797bfd05d4040fbf766198b3cfcc1838002cc890; version=e294c4c2d33b7307a89cdf31bec08a112d6a9297

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
PrivilegesUnavailable
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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