CVE-2026-55558: Improper Neutralization of Special Elements in Output Used by a Downstream Component

aiosmtplib is an asynchronous SMTP client for use with asyncio. Prior to 5.1.2, SMTPProtocol.starttls in src/aiosmtplib/protocol.py consumes the server's 220 response and starts the TLS handshake without clearing SMTPProtocol.buffer. An active network attacker can place attacker-chosen SMTP...