Remote code execution in OpenSMTPD

Published: 2020-01-29
Risk Critical
Patch available YES
Number of vulnerabilities 1
CVE ID CVE-2020-7247
Exploitation vector Network
Public exploit Public exploit code for vulnerability #1 is available.
Vulnerable software
Server applications / Mail servers

Vendor OpenBSD

Security Advisory

This security advisory describes one critical risk vulnerability.

1) OS Command Injection

Risk: Critical

CVSSv3: 9.3 [CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:F/RL:O/RC:C] [PCI]

CVE-ID: CVE-2020-7247

CWE-ID: CWE-78 - Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

Exploit availability: Yes


The vulnerability allows a remote attacker to execute arbitrary shell commands on the target system.

The vulnerability exists due to improper validation of user-supplied input passed within the smtp_mailaddr() function. A remote unauthenticated attacker can send a specially crafted MAIL FROM command and execute arbitrary OS commands on the target system with root privileges.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.


Install updates from vendor's website.

Vulnerable software versions

OpenSMTPD: 6.4.0, 6.4.0p1, 6.4.0p2, 6.4.1, 6.4.1p1, 6.4.1p2, 6.4.2, 6.4.2p1, 6.6.0, 6.6.0p1, 6.6.1, 6.6.1p1

CPE External links

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, a fully functional exploit for this vulnerability is available.