CVE-2026-89695Network attack vector

Remote service interruption via uncapped ACL sorting

Published Sep 11, 2026 · Updated Sep 11, 2026

Denial of service in Linux 7.0 allows remote attackers to consume unbounded nfsd CPU through a crafted NFSv4 POSIX ACL. nfsd4_decode_posixacl passes an uncapped wire-supplied entry count to allocation and an O(n²) bubble sort in sort_pacl_range. Reachability requires an NFS server with NFSv4 POSIX ACL decoding enabled; the demonstrated consequence is excessive CPU consumption in compound processing, with no reported data disclosure or modification.

CVSS severityUnavailable
Unscored
EPSS probability0.49%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Linux 7.0 allows remote attackers to consume unbounded nfsd CPU through a crafted NFSv4 POSIX ACL. nfsd4_decode_posixacl passes an uncapped wire-supplied entry count to allocation and an O(n²) bubble sort in sort_pacl_range. Reachability requires an NFS server with NFSv4 POSIX ACL decoding enabled; the demonstrated consequence is excessive CPU consumption in compound processing, with no reported data disclosure or modification.

The record

CVE
CVE-2026-89695
Published
Sep 11, 2026
Updated
Sep 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
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=5fc51dfc2eb160bd7ab3251ab1767cacf9c8bf05 <4bc1108e876153a2dd6d874052b99182c3603135
  2. Affected versionversion=5fc51dfc2eb160bd7ab3251ab1767cacf9c8bf05 <ea14d71d6ecb925673761bcf79f781f7dc9042cc
  3. Affected versionversion=7.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=5fc51dfc2eb160bd7ab3251ab1767cacf9c8bf05 <4bc1108e876153a2dd6d874052b99182c3603135; version=5fc51dfc2eb160bd7ab3251ab1767cacf9c8bf05 <ea14d71d6ecb925673761bcf79f781f7dc9042cc; version=7.0

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

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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