Opensmtpd

Opensmtpd is a lightweight, security-focused mail transfer agent widely embedded in Unix and Linux distributions, where its narrow product scope belies significant deployment breadth and attack surface value. Vulnerabilities affecting the vendor skew toward serious outcomes, with an elevated share reaching critical severity and a strong tendency toward public exploit availability, reflecting the memory-safety and input-parsing demands of a network-exposed daemon. The recurring weaknesses—including improper condition checking, memory-management flaws, NULL-pointer dereferences, and out-of-bounds reads—are characteristic of native C codebases handling untrusted SMTP protocol input. Current severity and exploitation status are shown alongside this summary.