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FedoraOperating system · Fedoraproject

CVE-2020-10700

MEDIUM · 5.3 CVSS v3.1 Published 2020-05-04
Fix available
A fix is available. Upgrade to 4.10.15 / 4.11.8 or later.
See remediation →
60/100
Remediation priority · Elevated
Remotely reachable No privileges

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 use-after-free flaw was found in the way samba AD DC LDAP servers, handled 'Paged Results' control is combined with the 'ASQ' control. A malicious user in a samba AD could use this flaw to cause denial of service. 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 use-after-free vulnerability exists in Samba's Active Directory Domain Controller LDAP server implementation. The flaw is triggered when processing LDAP requests that combine 'Paged Results' control with 'ASQ' (Attribute Scoped Query) control, leading to a use-after-free condition that can be exploited by a malicious authenticated user to cause a denial of service.

MitigationUpgrade Samba to version 4.10.15 or later, 4.11.8 or later, or 4.12.2 or later to address this vulnerability. If immediate upgrade is not feasible, consider restricting LDAP access to trusted users and implementing network-level access controls.

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= 32
SambaApplication
Affected:>= 4.10.0, < 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
High
Privileges
None
User interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/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. Identify Samba installation and version
    Run 'smbd --version' or 'samba --version' to obtain the installed Samba version number
    Affected if Version matches 4.10.0 through 4.10.14, 4.11.0 through 4.11.7, or 4.12.0 through 4.12.1
  2. Determine if Samba is configured as an Active Directory Domain Controller
    Check the Samba configuration file (smb.conf) for 'server role = active directory domain controller' or inspect the 'samba-tool domain info' output
    Affected if Samba is operating in the AD DC role, enabling the vulnerable LDAP server component
  3. Verify the LDAP server is enabled and running
    Check process list for 'samba' processes and verify LDAP ports (389, 636) are listening using 'netstat -tlnp | grep -E "389|636"' or 'ss -tlnp | grep -E "389|636"'
    Affected if The LDAP server daemon is active, exposing the vulnerable code path
  4. Confirm LDAP authenticated access is possible
    Verify that LDAP authentication is permitted for user accounts in the environment by reviewing LDAP bind configurations or testing with 'ldapsearch -x -D "CN=username,CN=Users,DC=domain" -W -h localhost'
    Affected if Authenticated LDAP users can connect to the server, which is required to trigger the use-after-free with the specific control combination

You are affected if Samba is running as an AD Domain Controller with an enabled LDAP server, the installed version falls within 4.10.0-4.10.14, 4.11.0-4.11.7, or 4.12.0-4.12.1, and untrusted authenticated LDAP users have access to the environment.

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 or later, 4.11.8 or later, or 4.12.2 or later to address this vulnerability. If immediate upgrade is not feasible, consider restricting LDAP access to trusted users and implementing network-level access controls.

Fix this in Fedora Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,240
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,984.

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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-2020-10700 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