CVE-2026-89670

Recycled-memory dereference via unprotected LOCALIO retry

Published Sep 11, 2026 · Updated Sep 11, 2026

Use-after-free in Linux kernel NFS LOCALIO 6.15.3 through 6.16 allows local users to dereference recycled memory during file opens. The nfsd_open_local_fh() retry path reads an nfsd_file pointer with cmpxchg and increments its reference count after the surrounding RCU read-side section has ended. Reachability requires a same-host NFS LOCALIO client and server race; the published record establishes neither code execution, disclosure, nor a deterministic crash.

CVSS severityUnavailable
Unscored
EPSS probability0.16%
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 kernel NFS LOCALIO 6.15.3 through 6.16 allows local users to dereference recycled memory during file opens. The nfsd_open_local_fh() retry path reads an nfsd_file pointer with cmpxchg and increments its reference count after the surrounding RCU read-side section has ended. Reachability requires a same-host NFS LOCALIO client and server race; the published record establishes neither code execution, disclosure, nor a deterministic crash.

The record

CVE
CVE-2026-89670
Published
Sep 11, 2026
Updated
Sep 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
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=6.15.3 <6.16
  2. Affected versionversion=6.16
  3. Affected versionversion=986a21ace186433e0397a59491646edad8c8d636
  4. Affected versionversion=e6f7e1487ab528a6c653bd0d42812ff2942846cd <559570f91a7d4d199a72105e4980bef791f4cbf1
  5. Affected versionversion=e6f7e1487ab528a6c653bd0d42812ff2942846cd <58884694978a3d7d111edb433d7fd6a6c5af2f34
  6. Affected versionversion=e6f7e1487ab528a6c653bd0d42812ff2942846cd <763c0bad872368304db718f79af7e93048885c67

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=6.15.3 <6.16; version=6.16; version=986a21ace186433e0397a59491646edad8c8d636; version=e6f7e1487ab528a6c653bd0d42812ff2942846cd <559570f91a7d4d199a72105e4980bef791f4cbf1; version=e6f7e1487ab528a6c653bd0d42812ff2942846cd <58884694978a3d7d111edb433d7fd6a6c5af2f34; version=e6f7e1487ab528a6c653bd0d42812ff2942846cd <763c0bad872368304db718f79af7e93048885c67

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)
Vectorlocal
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

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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