RHSA-2026:26564 — Security Advisory

An update for dovecot is now available for Red Hat Enterprise Linux 7 Extended Lifecycle Support.

Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

Dovecot is an IMAP server for Linux and other UNIX-like systems, written primarily with security in mind. It also contains a small POP3 server, and supports e-mail in either the maildir or mbox format. The SQL drivers and authentication plug-ins are provided as subpackages.

Security Fix(es):

• dovecot: Doveadm: Full access via timing oracle attack in credential verification (CVE-2026-27856)

• dovecot: ManageSieve: Denial of Service via crafted SASL initial response in AUTHENTICATE command (CVE-2025-59032)

• dovecot: denial of service via crafted message before authentication (CVE-2026-27858)

• dovecot: denial of service via specially crafted NOOP command (CVE-2026-27857)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.