CVE-2026-89659Network attack vectorHinoki check available

Use-after-free via unpinned delegation owner

Published Sep 11, 2026 · Updated Sep 11, 2026

Use-after-free in Linux NFSD allows attackers to access freed client memory during concurrent delegation revocation and client teardown. nfs4_laundromat removes an expired delegation from cl_delegations before revoke_delegation relinks it, letting client_has_state miss the bare nfs4_client pointer and free its owner. Reachability requires a recalled NFS delegation to time out while client teardown runs; published evidence establishes the invalid dereference but not code execution or a reliable crash.

CVSS severityUnavailable
Unscored
EPSS probability0.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Use-after-free in Linux NFSD allows attackers to access freed client memory during concurrent delegation revocation and client teardown. nfs4_laundromat removes an expired delegation from cl_delegations before revoke_delegation relinks it, letting client_has_state miss the bare nfs4_client pointer and free its owner. Reachability requires a recalled NFS delegation to time out while client teardown runs; published evidence establishes the invalid dereference but not code execution or a reliable crash.

The record

CVE
CVE-2026-89659
Published
Sep 11, 2026
Updated
Sep 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
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=3.10
  2. Affected versionversion=3bd64a5ba1719c2bb6cba4493dfd3e23a7653e54 <2a9d637c2a8fd8ac29ad9b29f28d122ef75c1a56
  3. Affected versionversion=3bd64a5ba1719c2bb6cba4493dfd3e23a7653e54 <3c0a53ee0b442348d8d2286d6960d3f07bb3a3d3
  4. Affected versionversion=3bd64a5ba1719c2bb6cba4493dfd3e23a7653e54 <4683ca76b3b7e5808338491c6eb3c20e6b4894d5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=3.10; version=3bd64a5ba1719c2bb6cba4493dfd3e23a7653e54 <2a9d637c2a8fd8ac29ad9b29f28d122ef75c1a56; version=3bd64a5ba1719c2bb6cba4493dfd3e23a7653e54 <3c0a53ee0b442348d8d2286d6960d3f07bb3a3d3; version=3bd64a5ba1719c2bb6cba4493dfd3e23a7653e54 <4683ca76b3b7e5808338491c6eb3c20e6b4894d5

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 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

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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