CVE-2020-7247: OpenSMTPD Remote Code Execution Vulnerability

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: yes — in CISA KEV since 2022-03-25
EPSS: 99.0% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2020-01-29 · updated 2026-06-17
Weakness: CWE-78

Description

smtp_mailaddr in smtp_session.c in OpenSMTPD 6.6, as used in OpenBSD 6.6 and other products, allows remote attackers to execute arbitrary commands as root via a crafted SMTP session, as demonstrated by shell metacharacters in a MAIL FROM field. This affects the "uncommented" default configuration. The issue exists because of an incorrect return value upon failure of input validation.

Affected products

Canonical Ubuntu Linux: 18.04, 19.10
Debian Linux: 9.0, 10.0
Fedoraproject Fedora: 32
OpenBSD Opensmtpd: 6.6

References

http://packetstormsecurity.com/files/156137/OpenBSD-OpenSMTPD-Privilege-Escalation-Code-Execution.html
http://packetstormsecurity.com/files/156145/OpenSMTPD-6.6.2-Remote-Code-Execution.html
http://packetstormsecurity.com/files/156249/OpenSMTPD-MAIL-FROM-Remote-Code-Execution.html
http://packetstormsecurity.com/files/156295/OpenSMTPD-6.6.1-Local-Privilege-Escalation.html
http://packetstormsecurity.com/files/162093/OpenBSD-OpenSMTPD-6.6-Remote-Code-Execution.html
http://seclists.org/fulldisclosure/2020/Jan/49
http://www.openwall.com/lists/oss-security/2020/01/28/3
https://github.com/openbsd/src/commit/9dcfda045474d8903224d175907bfc29761dcb45
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OPH4QU4DNVHA7ACFXMYFCEP5PSXXPN4E/
https://seclists.org/bugtraq/2020/Jan/51
https://usn.ubuntu.com/4268-1/
https://www.debian.org/security/2020/dsa-4611

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