Ubuntu Security Notice USN-4456-1
August 12, 2020
A security issue affects these releases of Ubuntu and its derivatives:
– Ubuntu 20.04 LTS
– Ubuntu 18.04 LTS
– Ubuntu 16.04 LTS
Several security issues were fixed in Dovecot.
– dovecot: IMAP and POP3 email server
It was discovered that Dovecot incorrectly handled deeply nested MIME
parts. A remote attacker could possibly use this issue to cause Dovecot to
consume resources, resulting in a denial of service. (CVE-2020-12100)
It was discovered that Dovecot incorrectly handled memory when using NTLM.
A remote attacker could possibly use this issue to cause Dovecot to crash,
resulting in a denial of service. (CVE-2020-12673)
It was discovered that the Dovecot RPA mechanism incorrectly handled
zero-length messages. A remote attacker could possibly use this issue to
cause Dovecot to crash, resulting in a denial of service. (CVE-2020-12674)
The problem can be corrected by updating your system to the following
Ubuntu 20.04 LTS:
Ubuntu 18.04 LTS:
Ubuntu 16.04 LTS:
In general, a standard system update will make all the necessary changes.
CVE-2020-12100, CVE-2020-12673, CVE-2020-12674