A Cyrus IMAP Server security update has been released for Ubuntu Linux 18.04 LTS.

USN-4566-1: Cyrus IMAP Server vulnerabilities

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Ubuntu Security Notice USN-4566-1
October 05, 2020

cyrus-imapd vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 18.04 LTS

Summary:

Cyrus IMAP Server could be made to overwrite files as the administrator.

Software Description:
- cyrus-imapd: An IMAP server

Details:

It was dicovered that Cyrus IMAP Server could execute arbitrary code via a
crafted HTTP PUT operation for an event with a long iCalendar property name.
An attacker could use this vulnerability to cause a crash or possibly execute
arbitrary code. (CVE-2019-11356)

It was discovered that the Cyrus IMAP Server allow users to create any
mailbox with administrative privileges. A local attacker could use this to
obtain sensitive information. (CVE-2019-19783)

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 18.04 LTS:
cyrus-admin 2.5.10-3ubuntu1.1
cyrus-caldav 2.5.10-3ubuntu1.1
cyrus-common 2.5.10-3ubuntu1.1
cyrus-imapd 2.5.10-3ubuntu1.1
cyrus-replication 2.5.10-3ubuntu1.1

In general, a standard system update will make all the necessary changes.

References:
  https://usn.ubuntu.com/4566-1
CVE-2019-11356, CVE-2019-19783

Package Information:
  https://launchpad.net/ubuntu/+source/cyrus-imapd/2.5.10-3ubuntu1.1