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FedoraOperating system · Fedoraproject

CVE-2020-10704

HIGH · 7.5 CVSS v3.1 Published 2020-05-06
Fix available
A fix is available. Upgrade to 4.10.15 / 4.11.8 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges 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
A flaw was found when using samba as an Active Directory Domain Controller. Due to the way samba handles certain requests as an Active Directory Domain Controller LDAP server, an unauthorized user can cause a stack overflow leading to a denial of service. The highest threat from this vulnerability is to system availability. This issue affects all samba versions before 4.10.15, before 4.11.8 and before 4.12.2.

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

A stack overflow vulnerability exists in Samba's LDAP server implementation when Samba is used as an Active Directory Domain Controller. An unauthenticated remote attacker can send specially crafted LDAP requests that trigger the stack overflow, causing a denial of service. The vulnerability affects all Samba versions before 4.10.15, 4.11.8, and 4.12.2.

MitigationUpgrade Samba to version 4.10.15, 4.11.8, 4.12.2 or later. Prior to upgrading, schedule maintenance windows and test in a staging environment since this is a critical infrastructure service.

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
FedoraOperating system
Affected:= 30= 31
Debian LinuxOperating system
Affected:= 9.0
SambaApplication
Affected:>= 4.0.0, < 4.10.15>= 4.11.0, < 4.11.8>= 4.12.0, < 4.12.2
LeapOperating system
Affected:= 15.2

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
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

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

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. Determine installed Samba version
    Run 'smbstatus --version' or 'samba --version' to obtain the Samba version number
    Affected if The version is less than 4.10.15, between 4.11.0 and 4.11.7, or between 4.12.0 and 4.12.1
  2. Confirm Samba is running as an Active Directory Domain Controller
    Check the Samba configuration file (smb.conf) for 'server role = active directory domain controller' or examine the output of 'samba-tool domain info 127.0.0.1'
    Affected if The 'server role' setting is set to 'active directory domain controller' or the samba-tool command returns valid AD DC information
  3. Verify LDAP server is enabled and listening
    Check if the LDAP ports (389 for LDAP, 636 for LDAPS) are open by running 'netstat -tulpn | grep -E "389|636"' or 'ss -tulpn | grep -E "389|636"'
    Affected if The LDAP ports are listening and exposed to network traffic, indicating the LDAP server is active
  4. Confirm AD DC LDAP service is exposed
    Run 'smbstatus -L' or check process list for 'samba' processes handling LDAP connections (such as 'ldap_server' or 'ldap child')
    Affected if LDAP-related Samba processes are running and the service is network-accessible rather than localhost-only

You are affected if your system runs a vulnerable Samba version (below 4.10.15, between 4.11.0-4.11.7, or between 4.12.0-4.12.1) AND is configured as an Active Directory Domain Controller with the LDAP server enabled and accessible on the network.

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 4.10.15 / 4.11.8 / 4.12.2 or later
Fixed in 4.10.154.11.84.12.2
Interim mitigation

Upgrade Samba to version 4.10.15, 4.11.8, 4.12.2 or later. Prior to upgrading, schedule maintenance windows and test in a staging environment since this is a critical infrastructure service.

Fix this in Fedora Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,130
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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-2020-10704 in production — separate from our analysis above.

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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