Related Vulnerabilities: CVE-2020-24386  

A security issue was discovered in dovecot version 2.2.26 up to 2.3.11.3. When imap hibernation is active, an attacker can cause dovecot to discover the file system directory structure and access other users' emails using a specially crafted command. The attacker must have valid credentials to access the mail server. The issue is fixed in dovecot version 2.3.13.

Severity High

Remote Yes

Type Information disclosure

Description

A security issue was discovered in dovecot version 2.2.26 up to 2.3.11.3. When imap hibernation is active, an attacker can cause dovecot to discover the file system directory structure and access other users' emails using a specially crafted command. The attacker must have valid credentials to access the mail server. The issue is fixed in dovecot version 2.3.13.

AVG-1398 dovecot 2.3.11.3-3 2.3.13-1 High Fixed

04 Jan 2021 ASA-202101-4 AVG-1398 dovecot High multiple issues

https://dovecot.org/pipermail/dovecot-news/2021-January/000450.html
https://github.com/dovecot/core/commit/00df2308b0733e810824545183d73276c416cdd3
https://github.com/dovecot/core/commit/b4a9872b833b7985c7d0e7615f1b7fc812dd4c55

Workaround
==========

Operators can choose to disable IMAP hibernation. IMAP hibernation is not on by default. To ensure imap hibernation is disabled, make sure imap_hibernate_timeout is set to 0 or unset.