CVE-2026-89708Network attack vector

Freed-memory access via callback teardown race

Published Sep 11, 2026 · Updated Sep 11, 2026

Use-after-free in Linux nfsd session teardown allows remote attackers to access freed kernel memory through NFSv4.1 callbacks. An asynchronous rpciod task can outlive DESTROY_SESSION processing and dereference cl_cb_session after free_session releases the session. Reachability requires an NFSv4.1 server, a destroyed session, and an in-flight callback; public materials establish no consequence beyond stale kernel-memory access.

CVSS severityUnavailable
Unscored
EPSS probability0.43%
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 nfsd session teardown allows remote attackers to access freed kernel memory through NFSv4.1 callbacks. An asynchronous rpciod task can outlive DESTROY_SESSION processing and dereference cl_cb_session after free_session releases the session. Reachability requires an NFSv4.1 server, a destroyed session, and an in-flight callback; public materials establish no consequence beyond stale kernel-memory access.

The record

CVE
CVE-2026-89708
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=2.6.38
  2. Affected versionversion=dcbeaa68dbbdacbbb330a86c7fc95a28473fc209 <01c5d5f58a5db9b0ee5afba2e49d3157788687b2
  3. Affected versionversion=dcbeaa68dbbdacbbb330a86c7fc95a28473fc209 <13bdd486c3aad4fc19e6d8b9c3556a4b4c190b25
  4. Affected versionversion=dcbeaa68dbbdacbbb330a86c7fc95a28473fc209 <f164eb52b6f3cbf40f07fe379f9f421f88e02f76

What conditions does exploitation require?

Attack vectornetwork
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.38; version=dcbeaa68dbbdacbbb330a86c7fc95a28473fc209 <01c5d5f58a5db9b0ee5afba2e49d3157788687b2; version=dcbeaa68dbbdacbbb330a86c7fc95a28473fc209 <13bdd486c3aad4fc19e6d8b9c3556a4b4c190b25; version=dcbeaa68dbbdacbbb330a86c7fc95a28473fc209 <f164eb52b6f3cbf40f07fe379f9f421f88e02f76

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 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

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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