CVE-2026-89703Network attack vector

Kernel use-after-free via unmarked delegation state

Published Sep 11, 2026 · Updated Sep 11, 2026

Use-after-free in Linux NFSD 6.11.6 through 6.12 allows remote attackers to access freed delegation memory via NFSv4 FREE_STATEID. nfsd4_drop_revoked_stid releases cl_lock without setting SC_STATUS_FREED, so revoke_delegation later adds the freed object to cl_revoked and __destroy_client traverses it. Reachability requires an NFSv4 client to hold an administrator-revoked delegation; the published record does not establish code execution or data disclosure.

CVSS severityUnavailable
Unscored
EPSS probability0.61%
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 6.11.6 through 6.12 allows remote attackers to access freed delegation memory via NFSv4 FREE_STATEID. nfsd4_drop_revoked_stid releases cl_lock without setting SC_STATUS_FREED, so revoke_delegation later adds the freed object to cl_revoked and __destroy_client traverses it. Reachability requires an NFSv4 client to hold an administrator-revoked delegation; the published record does not establish code execution or data disclosure.

The record

CVE
CVE-2026-89703
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=6.11.6 <6.12
  2. Affected versionversion=6.12
  3. Affected versionversion=8dd91e8d31febf4d9cca3ae1bb4771d33ae7ee5a <1e4795766719ffd74b8cf0f2fde4a1350f8326bf
  4. Affected versionversion=8dd91e8d31febf4d9cca3ae1bb4771d33ae7ee5a <650d370cfbc66a96dd14d517bd704689b5bda4e5
  5. Affected versionversion=8dd91e8d31febf4d9cca3ae1bb4771d33ae7ee5a <a6d89032e5c6620d5bb44582a72555ce07bf1c2e
  6. Affected versionversion=8dd91e8d31febf4d9cca3ae1bb4771d33ae7ee5a <d832a0587528853d45481d1faf75d4b5d062adaf
  7. Affected versionversion=967faa26f313a62e7bebc55d5b8122eaee43b929

What conditions does exploitation require?

Attack vectornetwork
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=6.11.6 <6.12; version=6.12; version=8dd91e8d31febf4d9cca3ae1bb4771d33ae7ee5a <1e4795766719ffd74b8cf0f2fde4a1350f8326bf; version=8dd91e8d31febf4d9cca3ae1bb4771d33ae7ee5a <650d370cfbc66a96dd14d517bd704689b5bda4e5; version=8dd91e8d31febf4d9cca3ae1bb4771d33ae7ee5a <a6d89032e5c6620d5bb44582a72555ce07bf1c2e; version=8dd91e8d31febf4d9cca3ae1bb4771d33ae7ee5a <d832a0587528853d45481d1faf75d4b5d062adaf; version=967faa26f313a62e7bebc55d5b8122eaee43b929

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 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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