CVE-2021-38084: Courier-MTA Courier Mail Server

High severity, CVSS 8.1. EPSS: 1.4% chance of exploitation in the next 30 days.

An issue was discovered in the POP3 component of Courier Mail Server before 1.1.5. Meddler-in-the-middle attackers can pipeline commands after the POP3 STLS command, injecting plaintext commands into an encrypted user session.

Affected products

• Courier-MTA Courier Mail Server: before 1.1.5 (fixed in 1.1.5)

Published 2021-08-03. Last modified 2026-06-17.