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Ubuntu LinuxOperating system · Canonical

CVE-2019-14902

MEDIUM · 5.4 CVSS v3.1 Published 2020-01-21
Fix available
A fix is available. Upgrade to 4.9.18 / 4.10.12 or later.
See remediation →
60/100
Remediation priority · Elevated
Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
There is an issue in all samba 4.11.x versions before 4.11.5, all samba 4.10.x versions before 4.10.12 and all samba 4.9.x versions before 4.9.18, where the removal of the right to create or modify a subtree would not automatically be taken away on all domain controllers.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

This is an access control synchronization vulnerability in Samba Active Directory domain controllers where removing the right to create or modify a subtree does not automatically propagate to all domain controllers. This creates inconsistent permission states across the domain, potentially allowing unauthorized subtree modifications on some DCs despite explicit revocation.

MitigationUpgrade Samba to version 4.11.5 or later (4.10.12+, 4.9.18+) on all domain controllers and verify that permission changes replicate correctly across the domain.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Ubuntu LinuxOperating system
Affected:= 16.04= 18.04= 19.04= 19.10
Debian LinuxOperating system
Affected:= 9.0
SambaApplication
Affected:>= 4.0.0, < 4.9.18>= 4.10.0, < 4.10.12>= 4.11.0, < 4.11.5
LeapOperating system
Affected:= 15.1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed Samba version
    Run 'samba --version' or check package manager (dpkg -l | grep samba, rpm -qa | grep samba)
    Affected if Version is >= 4.0.0 and < 4.9.18, OR >= 4.10.0 and < 4.10.12, OR >= 4.11.0 and < 4.11.5
  2. Confirm Samba is running as an Active Directory Domain Controller
    Check smb.conf for 'server role = active directory domain controller' or examine running processes for 'samba' AD DC services
    Affected if Samba is configured and running as an AD DC (not a file server or member server)
  3. Verify multiple Domain Controllers exist in the domain
    Run 'samba-tool drs showrepl' or check AD sites and services for more than one DC
    Affected if More than one DC exists in the domain, creating potential for replication inconsistency
  4. Identify permission changes on subtrees
    Review AD access control lists (ACLs) on organizational units (OUs) - use 'samba-tool dsacl' or Windows RSAT tools to examine ACEs that deny create/modify on subtrees
    Affected if Explicit deny or removal of create/modify rights was applied to OUs or containers after the Samba version was deployed
  5. Check replication status of directory partitions
    Run 'samba-tool drs bind' and 'samba-tool drs showrepl' to inspect last replication success times and any errors
    Affected if Replication shows failures, delays, or inconsistencies between DCs for the domain partition

You are affected if Samba is running as an AD DC with a version in the affected range and there are multiple DCs where subtree permission changes may not have fully replicated.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Upgrade available Upgrade to 4.9.18 / 4.10.12 / 4.11.5 or later
Fixed in 4.9.184.10.124.11.5
Interim mitigation

Upgrade Samba to version 4.11.5 or later (4.10.12+, 4.9.18+) on all domain controllers and verify that permission changes replicate correctly across the domain.

Fix this in Ubuntu Linux Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,490
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Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2019-14902 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data