CVE-2026-90236Network attack vector

Unmount denial via leaked export references

Published Sep 17, 2026 · Updated Sep 17, 2026

Reference leaks in Linux NFSD 7.2 allow remote authenticated users to block filesystem unmounts through NFSv4 state teardown. free_ol_stateid_reaplist() frees stateids without releasing sc_export, while nfs4_put_stid() reads that reference outside cl_lock, permitting a double release during concurrent revocation. An active NFSv4 server and client access sufficient to create open or lock state are required; the documented availability effect is blocked unmount, not a demonstrated kernel crash.

CVSS severity4.3
Medium
EPSS probability0.21%
Next 30 days · Oct 18, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reference leaks in Linux NFSD 7.2 allow remote authenticated users to block filesystem unmounts through NFSv4 state teardown. free_ol_stateid_reaplist() frees stateids without releasing sc_export, while nfs4_put_stid() reads that reference outside cl_lock, permitting a double release during concurrent revocation. An active NFSv4 server and client access sufficient to create open or lock state are required; the documented availability effect is blocked unmount, not a demonstrated kernel crash.

The record

CVE
CVE-2026-90236
Published
Sep 17, 2026
Updated
Sep 17, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 17, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 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=7.2
  2. Affected versionversion=ba0cde5dc81d214684b8ea0bd87414ba2f48fe02 <6480bd703684ed3f760e9e36c4a699033c0806ae
  3. Affected versionversion=ba0cde5dc81d214684b8ea0bd87414ba2f48fe02 <7458727fd7cb79d09e5120b6fecc1ad11cdb0946

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=7.2; version=ba0cde5dc81d214684b8ea0bd87414ba2f48fe02 <6480bd703684ed3f760e9e36c4a699033c0806ae; version=ba0cde5dc81d214684b8ea0bd87414ba2f48fe02 <7458727fd7cb79d09e5120b6fecc1ad11cdb0946

Published CVSS scores

4.3Amazon LinuxCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

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.

Activity data is delayed. The latest report is Sep 28, 2026.

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

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 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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