CVE-2019-18928

Cyrus IMAP 2.5.x before 2.5.14 and 3.x before 3.0.12 allows privilege escalation because an HTTP request may be interpreted in the authentication context of an unrelated previous request that arrived over the same connection.

If HTTP is enabled (e.g. RSS, CalDAV), cyrus-imapd does not properly authenticate a HTTP request coming through a connection that has been previously authenticated. Usually, this is not a problem, as each user will have their own connection and a breach of security boundaries would not be possible. An exception to this rule is if the cyrus-imapd HTTP service is behind a proxy, for example a reverse caching proxy, and said proxy reuses the same connection to cyrus-imapd for multiple requests.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.