AsyncSSH vulnerable to Prefix Truncation Attack (a.k.a. Terrapin Attack) against ChaCha20-Poly1305 and Encrypt-then-MAC

Summary AsyncSSH v2.14.1 and earlier is vulnerable to a novel prefix truncation attack a.k.a. Terrapin attack, which allows a man-in-the-middle attacker to strip an arbitrary number of messages right after the initial key exchange, breaking SSH extension negotiation RFC8308 in the process and thu...