Red Hat Security Advisory: dovecot security update
Multiple security vulnerabilities have been identified in Dovecot, an IMAP and POP3 server for Linux and UNIX-like systems. These include a timing oracle attack in credential verification allowing full access, and several denial of service (DoS) vulnerabilities triggered by crafted SASL initial responses, messages before authentication, and specially crafted NOOP commands. Red Hat has issued an important security advisory with updates for Red Hat Enterprise Linux 7 Extended Lifecycle Support to address these issues.
AI Analysis
Technical Summary
This advisory covers four vulnerabilities in Dovecot: CVE-2026-27856, a timing oracle attack in Doveadm credential verification that can lead to full access; CVE-2025-59032, a denial of service via a crafted SASL initial response in the AUTHENTICATE command in ManageSieve; CVE-2026-27858, a denial of service via a crafted message before authentication; and CVE-2026-27857, a denial of service via a specially crafted NOOP command. These vulnerabilities affect Red Hat Enterprise Linux Server Extended Life Cycle Support 7 versions. Red Hat has released updated packages to fix these issues as detailed in advisory RHSA-2026:26564.
Potential Impact
The timing oracle vulnerability (CVE-2026-27856) can allow an attacker to gain full access by exploiting credential verification timing differences. The other three vulnerabilities (CVE-2025-59032, CVE-2026-27858, CVE-2026-27857) can cause denial of service conditions, potentially disrupting mail services. These impacts are rated as important by Red Hat, indicating significant security concerns but no confirmed exploits in the wild have been reported.
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 these official patches as described in Red Hat advisory RHSA-2026:26564 and the referenced update article (https://access.redhat.com/articles/11258). No additional mitigations are indicated beyond applying the vendor-provided updates.
Red Hat Security Advisory: dovecot security update
Description
Multiple security vulnerabilities have been identified in Dovecot, an IMAP and POP3 server for Linux and UNIX-like systems. These include a timing oracle attack in credential verification allowing full access, and several denial of service (DoS) vulnerabilities triggered by crafted SASL initial responses, messages before authentication, and specially crafted NOOP commands. Red Hat has issued an important security advisory with updates for Red Hat Enterprise Linux 7 Extended Lifecycle Support to address these issues.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This advisory covers four vulnerabilities in Dovecot: CVE-2026-27856, a timing oracle attack in Doveadm credential verification that can lead to full access; CVE-2025-59032, a denial of service via a crafted SASL initial response in the AUTHENTICATE command in ManageSieve; CVE-2026-27858, a denial of service via a crafted message before authentication; and CVE-2026-27857, a denial of service via a specially crafted NOOP command. These vulnerabilities affect Red Hat Enterprise Linux Server Extended Life Cycle Support 7 versions. Red Hat has released updated packages to fix these issues as detailed in advisory RHSA-2026:26564.
Potential Impact
The timing oracle vulnerability (CVE-2026-27856) can allow an attacker to gain full access by exploiting credential verification timing differences. The other three vulnerabilities (CVE-2025-59032, CVE-2026-27858, CVE-2026-27857) can cause denial of service conditions, potentially disrupting mail services. These impacts are rated as important by Red Hat, indicating significant security concerns but no confirmed exploits in the wild have been reported.
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 these official patches as described in Red Hat advisory RHSA-2026:26564 and the referenced update article (https://access.redhat.com/articles/11258). No additional mitigations are indicated beyond applying the vendor-provided updates.
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: 6/17/2026, 4:46:49 PM
Last enriched: 6/17/2026, 5:05:41 PM
Last updated: 6/17/2026, 6:23:31 PM
Views: 2
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