Red Hat Security Advisory: dovecot security update
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.
AI Analysis
Technical Summary
This advisory covers four vulnerabilities in Dovecot: CVE-2026-27856 allows full access through a timing oracle attack in credential verification via the Doveadm utility; CVE-2025-59032 enables denial of service through a crafted SASL initial response in the ManageSieve AUTHENTICATE command; CVE-2026-27858 causes denial of service via a crafted message before authentication; and CVE-2026-27857 results in denial of service via a specially crafted NOOP command. These vulnerabilities affect Red Hat Enterprise Linux Server Extended Lifecycle Support 7 on multiple architectures. Red Hat has released updated packages to remediate these issues as detailed in advisory RHSA-2026:26564.
Potential Impact
Successful exploitation of CVE-2026-27856 can lead to full access through credential verification bypass. The other three vulnerabilities (CVE-2025-59032, CVE-2026-27857, CVE-2026-27858) can cause denial of service conditions, potentially disrupting mail services. No known exploits in the wild have been reported at this time.
Mitigation Recommendations
Red Hat has released updated Dovecot packages for Red Hat Enterprise Linux 7 Extended Lifecycle Support to address these vulnerabilities. Users should apply the official security update as described in Red Hat advisory RHSA-2026:26564 and the referenced article https://access.redhat.com/articles/11258. No alternative mitigations are indicated by the vendor advisory.
Red Hat Security Advisory: dovecot security update
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: 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.
Affected software
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This advisory covers four vulnerabilities in Dovecot: CVE-2026-27856 allows full access through a timing oracle attack in credential verification via the Doveadm utility; CVE-2025-59032 enables denial of service through a crafted SASL initial response in the ManageSieve AUTHENTICATE command; CVE-2026-27858 causes denial of service via a crafted message before authentication; and CVE-2026-27857 results in denial of service via a specially crafted NOOP command. These vulnerabilities affect Red Hat Enterprise Linux Server Extended Lifecycle Support 7 on multiple architectures. Red Hat has released updated packages to remediate these issues as detailed in advisory RHSA-2026:26564.
Potential Impact
Successful exploitation of CVE-2026-27856 can lead to full access through credential verification bypass. The other three vulnerabilities (CVE-2025-59032, CVE-2026-27857, CVE-2026-27858) can cause denial of service conditions, potentially disrupting mail services. No known exploits in the wild have been reported at this time.
Mitigation Recommendations
Red Hat has released updated Dovecot packages for Red Hat Enterprise Linux 7 Extended Lifecycle Support to address these vulnerabilities. Users should apply the official security update as described in Red Hat advisory RHSA-2026:26564 and the referenced article https://access.redhat.com/articles/11258. No alternative mitigations are indicated by the vendor advisory.
Technical Details
- Gcve Source
- db.gcve.eu
- Csaf Category
- csaf_security_advisory
- Csaf Version
- 2.0
- Publisher
- Red Hat Product Security
- Advisory Id
- RHSA-2026:26564
- Cve Count
- 4
- Additional Cves
- ["CVE-2026-27856","CVE-2026-27857","CVE-2026-27858"]
- Cvss Version
- null
Threat ID: 6a32cf799f87a2db092a8e0b
Added to database: 06/17/2026, 16:46:49 UTC
Last enriched: 06/25/2026, 23:23:56 UTC
Last updated: 08/01/2026, 07:17:57 UTC
Views: 160
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