Open-Xchange Security Advisory 2019-04-30 Product: Dovecot Vendor: OX Software GmbH Internal reference: DOV-3223 (Bug ID) Vulnerability type: CWE-617 Vulnerable version: 2.3.0 - 2.3.5.2 Vulnerable component: submission-login Report confidence: Confirmed Solution status: Fixed by Vendor Fixed version: 2.3.6 Vendor notification: 2019-03-11 Solution date: 2019-04-23 Public disclosure: 2019-04-30 CVE reference: CVE-2019-11499 CVSS: 7.5 (CVSS3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) Vulnerability Details: Submission-login crashes when authentication is started over TLS secured channel and invalid authentication message is sent. This can lead to denial-of-service attack by persistent attacker(s). Workaround: Authentication crash can be avoided if authentication is done without TLS. Solution: Operators should upgrade to a fixed version.