Red Hat Product Errata RHSA-2026:19364 - Security Advisory Issued: 2026-05-19 Updated: 2026-05-19 RHSA-2026:19364 - Security Advisory Overview Synopsis Important: dovecot security update Type/Severity Security Advisory: Important Topic An update for dovecot is now available for Red Hat Enterprise Linux 9. 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. Description 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: 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. Solution For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Affected Products Red Hat Enterprise Linux for x86_64 9 x86_64 Red Hat Enterprise Linux for x86_64 - Extended Update Support 9.8 x86_64 Red Hat Enterprise Linux for IBM z Systems 9 s390x Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 9.8 s390x Red Hat Enterprise Linux for Power, little endian 9 ppc64le Red Hat Enterprise Linux for Power, little endian - Extended Update Support 9.8 ppc64le Red Hat Enterprise Linux for ARM 64 9 aarch64 Red Hat Enterprise Linux for ARM 64 - Extended Update Support 9.8 aarch64 Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions 9.8 ppc64le Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 9.8 x86_64 Red Hat CodeReady Linux Builder for x86_64 9 x86_64 Red Hat CodeReady Linux Builder for Power, little endian 9 ppc64le Red Hat CodeReady Linux Builder for ARM 64 9 aarch64 Red Hat CodeReady Linux Builder for IBM z Systems 9 s390x Red Hat CodeReady Linux Builder for x86_64 - Extended Update Support 9.8 x86_64 Red Hat CodeReady Linux Builder for Power, little endian - Extended Update Support 9.8 ppc64le Red Hat CodeReady Linux Builder for IBM z Systems - Extended Update Support 9.8 s390x Red Hat CodeReady Linux Builder for ARM 64 - Extended Update Support 9.8 aarch64 Red Hat Enterprise Linux for ARM 64 - 4 years of updates 9.8 aarch64 Red Hat Enterprise Linux for IBM z Systems - 4 years of updates 9.8 s390x Red Hat Enterprise Linux for x86_64 - Extended Life Cycle 9.8 x86_64 Red Hat Enterprise Linux for ARM 64 - Extended Life Cycle 9.8 aarch64 Red Hat Enterprise Linux for Power, little endian - Extended Life Cycle 9.8 ppc64le Red Hat Enterprise Linux for IBM z Systems - Extended Life Cycle 9.8 s390x Fixes BZ - 2452172 - CVE-2025-59032 dovecot: ManageSieve: Denial of Service via crafted SASL initial response in AUTHENTICATE command BZ - 2452175 - CVE-2026-27858 dovecot: denial of service via crafted message before authentication BZ - 2452179 - CVE-2026-27857 dovecot: denial of service via specially crafted NOOP command CVEs CVE-2025-59032 CVE-2026-27857 CVE-2026-27858 References https://access.redhat.com/security/updates/classification/#important The Red Hat security contact is secalert@redhat.com . More contact details at https://access.redhat.com/security/team/contact/ .