CVE-2026-93786Network attack vector

Permission widening via overwritten inherited ACL mask

Published Sep 24, 2026 · Updated Sep 24, 2026

Incorrect permission assignment in Linux ksmbd allows remote authenticated users to widen effective permissions through SMB object creation. After VFS computes a child's inherited ACL, ksmbd_vfs_inherit_posix_acl() changes ACL_MASK to full rwx and reapplies the parent ACL, overwriting the child's access and default ACLs. Exposure requires an enabled ksmbd share on a POSIX-ACL filesystem, a parent default ACL with a restrictive mask, and permission to create a file or directory.

CVSS severityUnavailable
Unscored
EPSS probability0.34%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect permission assignment in Linux ksmbd allows remote authenticated users to widen effective permissions through SMB object creation. After VFS computes a child's inherited ACL, ksmbd_vfs_inherit_posix_acl() changes ACL_MASK to full rwx and reapplies the parent ACL, overwriting the child's access and default ACLs. Exposure requires an enabled ksmbd share on a POSIX-ACL filesystem, a parent default ACL with a restrictive mask, and permission to create a file or directory.

The record

CVE
CVE-2026-93786
Published
Sep 24, 2026
Updated
Sep 24, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1222.002
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 24, 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=0 <6.12.111
  2. Affected versionversion=0 <6.18.53
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <0093909becbda22b62b39b654dbc607faed59cd0
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <591acf171644de590cda245fd8595b473a1beb70
  5. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e148e567a9252643baa125cb65d7ae9c2c6cf68a

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=0 <6.12.111; version=0 <6.18.53; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <0093909becbda22b62b39b654dbc607faed59cd0; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <591acf171644de590cda245fd8595b473a1beb70; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e148e567a9252643baa125cb65d7ae9c2c6cf68a

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.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

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