CVE-2020-1946

Command execution via malicious header rules

Published Mar 25, 2021 · Updated Feb 13, 2025

OS command injection in Apache SpamAssassin before 3.4.5 allows remote attackers to execute commands through malicious .cf rules. The Conf::Parser header-rule parser accepts crafted rule syntax from loaded .cf files and permits it to reach a command-execution path. Exploitation requires an attacker-controlled rules file to be installed or retrieved, and commands run with the SpamAssassin process account's access.

CVSS severity9.8
Critical
EPSS probability6.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

OS command injection in Apache SpamAssassin before 3.4.5 allows remote attackers to execute commands through malicious .cf rules. The Conf::Parser header-rule parser accepts crafted rule syntax from loaded .cf files and permits it to reach a command-execution path. Exploitation requires an attacker-controlled rules file to be installed or retrieved, and commands run with the SpamAssassin process account's access.

The record

CVE
CVE-2020-1946
Published
Mar 25, 2021
Updated
Feb 13, 2025
Vendor
The Apache Software Foundation
Product
Apache SpamAssassin
Classifications
CWE-78, T1059
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Mar 25, 2021CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=Apache SpamAssassin <3.4.5

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

The Apache Software Foundation · Apache SpamAssassinversion=Apache SpamAssassin <3.4.5

Published CVSS scores

10.0National Vulnerability DatabaseAV:N/AC:L/Au:N/C:C/I:C/A:C
9.8National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
T1059Command and Scripting Interpreter

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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