CVE-2026-89671Network attack vector

Remote ACL deletion via unchecked SETACL mask

Published Sep 11, 2026 · Updated Sep 11, 2026

Improper ACL handling in Linux kernel NFSv3 server code allows remote attackers to delete directory ACLs through SETACL requests. nfsd3_proc_setacl() passes both decoded ACL pointers to set_posix_acl() without checking their mask bits, so an omitted pointer remains NULL and is interpreted as an ACL-removal request. Reachability requires access to issue SETACL against an exported directory; an access-only request removes its default ACL, while a zero mask removes both ACL types.

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

Improper ACL handling in Linux kernel NFSv3 server code allows remote attackers to delete directory ACLs through SETACL requests. nfsd3_proc_setacl() passes both decoded ACL pointers to set_posix_acl() without checking their mask bits, so an omitted pointer remains NULL and is interpreted as an ACL-removal request. Reachability requires access to issue SETACL against an exported directory; an access-only request removes its default ACL, while a zero mask removes both ACL types.

The record

CVE
CVE-2026-89671
Published
Sep 11, 2026
Updated
Sep 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1222.002
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=2.6.13
  2. Affected versionversion=a257cdd0e2179630d3201c32ba14d7fcb3c3a055 <453d7198a0ab07a12d46e0575861ac7b932da17e
  3. Affected versionversion=a257cdd0e2179630d3201c32ba14d7fcb3c3a055 <68a80b26efdff1d09f8ae1773c6a915abb9e191d
  4. Affected versionversion=a257cdd0e2179630d3201c32ba14d7fcb3c3a055 <b3bff820d068ea59767d4e91a3258231a879da5f
  5. Affected versionversion=a257cdd0e2179630d3201c32ba14d7fcb3c3a055 <ff99ed007f065198fd723152405c22aa558f700b

What conditions does exploitation require?

Attack vectornetwork
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.13; version=a257cdd0e2179630d3201c32ba14d7fcb3c3a055 <453d7198a0ab07a12d46e0575861ac7b932da17e; version=a257cdd0e2179630d3201c32ba14d7fcb3c3a055 <68a80b26efdff1d09f8ae1773c6a915abb9e191d; version=a257cdd0e2179630d3201c32ba14d7fcb3c3a055 <b3bff820d068ea59767d4e91a3258231a879da5f; version=a257cdd0e2179630d3201c32ba14d7fcb3c3a055 <ff99ed007f065198fd723152405c22aa558f700b

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

T1222.002File and Directory Permissions Modification: Linux and Mac File and Directory Permissions

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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