Open-Xchange Security Advisory 2021-01-04 Product: Dovecot Vendor: OX Software GmbH Internal reference: DOP-2009 (Bug ID) Vulnerability type: CWE-150: Improper Neutralization of Escape, Meta, or Control Sequences Vulnerable version: 2.2.26-2.3.11.3 Vulnerable component: imap Report confidence: Confirmed Solution status: Fixed by Vendor Fixed version: 2.3.13 Vendor notification: 2020-08-17 Solution date: 2020-08-27 Public disclosure: 2021-01-04 CVE reference: CVE-2020-24386 CVSS: 8.2 (CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N) Vulnerability Details: When imap hibernation is active, an attacker can cause Dovecot to discover file system directory structure and access other users' emails using specially crafted command. The attacker must have valid credentials to access the mail server. Risk: Attacker can access other users' emails and filesystem information. 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. Solution: Operators should update to 2.3.13 or later version.