CVE-2026-89688Network attack vectorHinoki check available

Service hang via mismatched replay reference release

Published Sep 11, 2026 · Updated Sep 11, 2026

Reference-counting error in Linux nfsd 6.10 allows remote attackers to stall NFSv4 state closure through a sequence-operation replay retry. When nfsd4_cstate_assign_replay returns -EAGAIN, the error path releases an unacquired stateowner reference instead of its held stateid reference, risking stateowner underflow and use-after-free while leaking the stateid reference. Reachability requires the replay owner to be undergoing teardown; the leaked reference can leave a concurrent close operation waiting indefinitely.

CVSS severityUnavailable
Unscored
EPSS probability0.61%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Reference-counting error in Linux nfsd 6.10 allows remote attackers to stall NFSv4 state closure through a sequence-operation replay retry. When nfsd4_cstate_assign_replay returns -EAGAIN, the error path releases an unacquired stateowner reference instead of its held stateid reference, risking stateowner underflow and use-after-free while leaking the stateid reference. Reachability requires the replay owner to be undergoing teardown; the leaked reference can leave a concurrent close operation waiting indefinitely.

The record

CVE
CVE-2026-89688
Published
Sep 11, 2026
Updated
Sep 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
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=6.10
  2. Affected versionversion=eec7620800081e27dbf8019ac2e66259f0d5bf6f <00843074d9b84824552c9679d423d29500ca5de0
  3. Affected versionversion=eec7620800081e27dbf8019ac2e66259f0d5bf6f <5e4627d3513e60accfce9d5f4c7fa95251ef93d6
  4. Affected versionversion=eec7620800081e27dbf8019ac2e66259f0d5bf6f <69ed78b6b947c9257213164678b4edf17533093b
  5. Affected versionversion=eec7620800081e27dbf8019ac2e66259f0d5bf6f <f7cb90ddc021747fc9abfd4cf5252d425fd34eec

What conditions does exploitation require?

Attack vectornetwork
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=6.10; version=eec7620800081e27dbf8019ac2e66259f0d5bf6f <00843074d9b84824552c9679d423d29500ca5de0; version=eec7620800081e27dbf8019ac2e66259f0d5bf6f <5e4627d3513e60accfce9d5f4c7fa95251ef93d6; version=eec7620800081e27dbf8019ac2e66259f0d5bf6f <69ed78b6b947c9257213164678b4edf17533093b; version=eec7620800081e27dbf8019ac2e66259f0d5bf6f <f7cb90ddc021747fc9abfd4cf5252d425fd34eec

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

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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