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SpamassassinApplication · Apache

CVE-2020-1946

CRITICAL · 9.8 CVSS v3.1 Published 2021-03-25
Fix available
A fix is available. Upgrade to 3.4.5 or later.
See remediation →
100/100
Remediation priority · Urgent
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
In Apache SpamAssassin before 3.4.5, malicious rule configuration (.cf) files can be configured to run system commands without any output or errors. With this, exploits can be injected in a number of scenarios. In addition to upgrading to SA version 3.4.5, users should only use update channels or 3rd party .cf files from trusted places.

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

Apache SpamAssassin before 3.4.5 contains a critical vulnerability where malicious rule configuration (.cf) files can execute system commands silently without generating any output or errors. This allows attackers to inject exploits through untrusted rule files, achieving arbitrary command execution on the affected system.

MitigationImmediately upgrade to SpamAssassin 3.4.5 or later, and audit all existing .cf rule files to remove any untrusted or suspicious configurations. Implement a policy to only use update channels and third-party .cf files from known trusted sources.

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
SpamassassinApplication
Affected:< 3.4.5
Debian LinuxOperating system
Affected:= 9.0= 10.0
FedoraOperating system
Affected:= 32= 33= 34

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
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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. Check the installed SpamAssassin version
    Run 'spamassassin --version' or 'sa-learn --version' to display the version number
    Affected if The reported version is lower than 3.4.5 (for example, 3.4.4, 3.4.3, etc.)
  2. Identify loaded .cf configuration files
    Run 'spamassassin -D --lint 2>&1 | grep -i "loading"' or check the spamassassin configuration for lines starting with 'loadplugin' or 'include' to see which .cf files are being loaded
    Affected if Any .cf files are loaded from directories outside the default trusted system paths (e.g., from user home directories, /tmp, or untrusted third-party sources)
  3. Review the sa-update or rule update configuration
    Check /etc/spamassassin/local.cf and any files in /etc/spamassassin/ for 'sa-update' or 'external sources' configuration, and look for custom 'include' or 'loadplugin' directives pointing to untrusted locations
    Affected if The configuration loads rules or updates from unverified or third-party sources not from the official SpamAssassin project
  4. Check for untrusted custom .cf files in user-accessible locations
    Inspect directories such as ~/.spamassassin/, /var/lib/spamassassin/, or any custom path specified in the configuration for .cf files that may have been added by untrusted parties
    Affected if Any .cf files exist in user-writable or untrusted directories that are being loaded by SpamAssassin

You are affected if your installed SpamAssassin version is below 3.4.5 AND your configuration loads .cf rule files from untrusted or non-official sources.

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.

dbcve · scoped
Upgrade available Upgrade to 3.4.5 or later
Fixed in 3.4.5
Interim mitigation

Immediately upgrade to SpamAssassin 3.4.5 or later, and audit all existing .cf rule files to remove any untrusted or suspicious configurations. Implement a policy to only use update channels and third-party .cf files from known trusted sources.

Recommended fix High confidence

SpamAssassin 3.4.5 or later

  1. Check current SpamAssassin version: spamassassin --version
  2. For Debian/Ubuntu: Run 'apt-get update && apt-get install spamassassin' to upgrade to the latest available version
  3. For Fedora: Run 'dnf update spamassassin' to upgrade to the latest available version
  4. Verify the upgrade was successful by checking the version is 3.4.5 or later: spamassassin --version
  5. Restart the spamassassin service to load the new version: systemctl restart spamassassin (or appropriate service name for your system)
  6. Review and ensure only trusted rule configuration (.cf) files are in use, as the vulnerability can be exploited via malicious rule files
Caveat Minor - upgrading SpamAssassin is generally safe; review custom rules for compatibility with the new version

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

Fix this in Spamassassin Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing6.0 h
  • Review / QA3.0 h
27.0 hours of engineering $4,800
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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-2020-1946 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