CVE-2020-1946: In Apache SpamAssassin before 3.4.5, malicious rule configuration (.cf) files can be configured to run system

Q: How do I fix CVE-2020-1946?

spamassassin: upgrade to 3.4.5; debian linux: mitigate or apply the listed mitigation; fedora: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2020-1946 being exploited?

CVE-2020-1946 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2020-1946 affect?

CVE-2020-1946 affects spamassassin, debian linux, fedora. Severity is critical (CVSS 9.8). 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 S

Q: How urgent is CVE-2020-1946?

Priority 68/100. Critical severity; EPSS top 7%: very likely to be exploited; Remotely exploitable, no login, no user action; On your watchlist

This week

CRITICAL 9.8REMOTEWATCHLISTUPGRADEMITIGATEMITIGATE

CVE-2020-1946 is a critical-severity flaw (CVSS 9.8) affecting spamassassin, debian linux, fedora. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Critical severity
EPSS top 7%: very likely to be exploited
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	6.1% (top 7%)
CISA exploited list	No
Weakness	CWE-78
Published	2021-03-25
Last modified	2026-06-17

Publisher (CNA): Apache Software Foundation · Vendor: apache · debian · fedoraproject

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-03-25 10:15 UTCPublished CVE record published
2026-06-17 03:02 UTCUpdated Record last modified

apache spamassassin UPGRADE

Affected: < 3.4.5

Fixed in: 3.4.5

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy spamassassin || rpm -q spamassassin || spamassassin --version

2. UPGRADE to 3.4.5 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade spamassassin

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade spamassassin

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

debian debian linux MITIGATE

Affected: 9.0 · 10.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 9.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

fedoraproject fedora MITIGATE

Affected: 32 · 33 · 34

Fixed in: no fixed release known

Safe to downgrade to: a release before 32

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2020-1946?

spamassassin: upgrade to 3.4.5; debian linux: mitigate or apply the listed mitigation; fedora: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2020-1946 being exploited?

CVE-2020-1946 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2020-1946 affect?

CVE-2020-1946 affects spamassassin, debian linux, fedora. Severity is critical (CVSS 9.8). 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 S

How urgent is CVE-2020-1946?

Priority 68/100. Critical severity; EPSS top 7%: very likely to be exploited; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Debian vulnerabilities

Related CVEs

CVE-2020-1931 HIGH 8.1 UPGRADE A command execution issue was found in Apache SpamAssassin prior to 3.4.3
CVE-2020-1930 HIGH 8.1 UPGRADE A command execution issue was found in Apache SpamAssassin prior to 3.4.3
CVE-2019-12420 HIGH 7.5 UPGRADE MITIGATE In Apache SpamAssassin before 3.4.3, a message can be crafted in a way to use excessive resources
CVE-2018-11805 MEDIUM 6.7 UPGRADE MITIGATE In Apache SpamAssassin before 3.4.3, nefarious CF files can be configured to run system commands without any o
CVE-2018-11781 HIGH 7.8 UPGRADE MITIGATE Apache SpamAssassin 3.4.2 fixes a local user code injection in the meta rule syntax.

References

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