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Debian LinuxOperating system · Debian

CVE-2020-25719

HIGH · 7.2 CVSS v3.1 Published 2022-02-18
Patch available
A vendor patch is available. No clean upgrade release — apply the published patch.
See remediation →
78/100
Remediation priority · High
Remotely reachable Zero-click Patch available

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 in the way Samba, as an Active Directory Domain Controller, implemented Kerberos name-based authentication. The Samba AD DC, could become confused about the user a ticket represents if it did not strictly require a Kerberos PAC and always use the SIDs found within. The result could include total domain compromise.

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
How this class of weakness works · CWE-287

The mechanism that verifies who a user is can be side-stepped or fooled, letting an attacker act as someone they're not. Everything built on top of that identity then becomes untrustworthy. Fixing it means hardening the full authentication flow, including edge cases, tokens, and secondary paths.

General guidance for the improper authentication class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

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
Debian LinuxOperating system
Affected:= 9.0= 10.0
FedoraOperating system
Affected:= 33= 34= 35
Ubuntu LinuxOperating system
Affected:= 20.04= 21.04= 21.10
Enterprise LinuxOperating system
Affected:= 7.0= 8.0
Enterprise Linux DesktopOperating system
Affected:= 7.0
Enterprise Linux EusOperating system
Affected:= 8.2= 8.4
Enterprise Linux For Ibm Z SystemsOperating system
Affected:= 7.0= 8.0
Enterprise Linux For Ibm Z Systems EusOperating system
Affected:= 8.2= 8.4

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

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

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.

dbcve · scoped
Patch available Apply the vendor patch
Vendor patch bugzilla.redhat.com →
Recommended fix High confidence

Samba 4.13.17, 4.14.12, or 4.15.5 or later (check distribution-specific security advisories for exact package versions)

  1. Check current Samba version installed: rpm -qa | grep samba or dpkg -l | grep samba
  2. Identify the Samba packages installed (samba, samba-common, samba-winbind, etc.)
  3. For RHEL/CentOS/Enterprise Linux: Run 'yum update samba' or 'dnf update samba'
  4. For Debian/Ubuntu: Run 'apt-get update && apt-get install samba'
  5. For Fedora: Run 'dnf update samba'
  6. After update, verify the new Samba version matches a fixed release (4.13.17+, 4.14.12+, or 4.15.5+)
  7. If running as an Active Directory Domain Controller, restart Samba services: 'systemctl restart smbd' 'systemctl restart nmbd' 'systemctl restart winbind' (or samba-ad-dc)
  8. Verify services are running: 'systemctl status samba-ad-dc' or check AD DC functionality
Caveat Ensure Samba configuration is compatible with new version; review release notes for deprecations; test in non-production environment first

Generated from the published advisory — verify against the referenced sources before acting.

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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-2020-25719 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
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