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.
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alpine Linux | — | Upgrade opensmtpd | Aug 22, 2024 | Jan 29, 2020 |
| Arch Linux | — | Upgrade to the latest version of Arch Linux | Jul 11, 2025 | Jan 29, 2020 |
| Debian | — | Upgrade opensmtpd | Jan 31, 2020 | Jan 29, 2020 |
| Freebsd | — | Upgrade opensmtpd | Jan 31, 2020 | Jan 29, 2020 |
| Ubuntu | — | Upgrade opensmtpdUpgrade opensmtpd (Ubuntu Pro) | Feb 6, 2020 | Jan 29, 2020 |
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