Dovecot before 2.3.13 has Improper Input Validation in lda, lmtp, and imap, leading to an application crash via a crafted email message with certain choices for ten thousand MIME parts.

An issue was discovered in Dovecot before 2.3.13. By using IMAP IDLE, an authenticated attacker can trigger unhibernation via attacker-controlled parameters, leading to access to other users' email messages (and path disclosure).