CVE-2020-7247
OpenSMTPD Remote Code Execution Vulnerability
OpenBSD OpenSMTPD
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.
Exploitation status
CISA Known Exploited Vulnerabilities
Listed by CISA on 25 March 2022. US federal agencies were required to remediate it by 15 April 2022.
EPSS — exploitation probability
FIRST puts the probability of exploitation activity in the next 30 days at 99%, which is higher than 99.9% of all scored vulnerabilities. EPSS is a forecast of activity, not a measure of severity, and it is rescored daily.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Frequently asked questions
Is CVE-2020-7247 being exploited by ransomware groups?
No ransomware group in this database is currently recorded as exploiting CVE-2020-7247.
What does CVE-2020-7247 affect?
CVE-2020-7247 affects OpenBSD OpenSMTPD. 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.
How severe is CVE-2020-7247?
CVE-2020-7247 is rated CRITICAL with a CVSS base score of 9.8. EPSS puts the probability of exploitation in the next 30 days at 99%, higher than 99.9% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 15 April 2022.
How should organisations respond to CVE-2020-7247?
Apply the vendor patch for OpenBSD OpenSMTPD as the first priority, and treat any internet-facing instance as the most urgent. Because this vulnerability is associated with ransomware activity, also review whether the affected systems were reachable before patching, rather than assuming that patching alone closes the incident.