CVE-2026-89683Network attack vector

Service interruption via leaked V4ROOT dentry references

Published Sep 11, 2026 · Updated Sep 11, 2026

Resource leakage in Linux kernel 6.12 nfsd allows remote attackers to exhaust memory through crafted NFSv3 filehandles. nfsd_set_fh_dentry() exits the V4ROOT branches after exportfs_decode_fh_raw() without calling dput(), while fh_dentry remains unset and fh_put() cannot release the reference. An NFS server must expose a V4ROOT export, and repeated requests retain dentry references until service availability degrades.

CVSS severityUnavailable
Unscored
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource leakage in Linux kernel 6.12 nfsd allows remote attackers to exhaust memory through crafted NFSv3 filehandles. nfsd_set_fh_dentry() exits the V4ROOT branches after exportfs_decode_fh_raw() without calling dput(), while fh_dentry remains unset and fh_put() cannot release the reference. An NFS server must expose a V4ROOT export, and repeated requests retain dentry references until service availability degrades.

The record

CVE
CVE-2026-89683
Published
Sep 11, 2026
Updated
Sep 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.002
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=6.12
  2. Affected versionversion=ef7f6c4904d03ccd7478e1ac20ed75f79c4ac444 <11db8df188b34bdb8c6a3a0bf438e5fc8cd75aca
  3. Affected versionversion=ef7f6c4904d03ccd7478e1ac20ed75f79c4ac444 <6247023fbbec1325029f2d5f2a7cdc0f9f9ea15a
  4. Affected versionversion=ef7f6c4904d03ccd7478e1ac20ed75f79c4ac444 <c1ae0f973bcba5730871e35976a0ab6878fdac34
  5. Affected versionversion=ef7f6c4904d03ccd7478e1ac20ed75f79c4ac444 <d493cf57f4c4dae5396cd6ad41e5c209d0615a81

What conditions does exploitation require?

Attack vectornetwork
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=6.12; version=ef7f6c4904d03ccd7478e1ac20ed75f79c4ac444 <11db8df188b34bdb8c6a3a0bf438e5fc8cd75aca; version=ef7f6c4904d03ccd7478e1ac20ed75f79c4ac444 <6247023fbbec1325029f2d5f2a7cdc0f9f9ea15a; version=ef7f6c4904d03ccd7478e1ac20ed75f79c4ac444 <c1ae0f973bcba5730871e35976a0ab6878fdac34; version=ef7f6c4904d03ccd7478e1ac20ed75f79c4ac444 <d493cf57f4c4dae5396cd6ad41e5c209d0615a81

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.002Service Exhaustion Flood

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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