RHEL 9 : dovecot (RHSA-2026:13857)

high Nessus Plugin ID 312286

Synopsis

The remote Red Hat host is missing one or more security updates for dovecot.

Description

The remote Redhat Enterprise Linux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:13857 advisory.

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.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Update the RHEL dovecot package based on the guidance in RHSA-2026:13857.

Plugin Details

Severity: High

ID: 312286

File Name: redhat-RHSA-2026-13857.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Red Hat Local Security Checks

Published: 5/5/2026

Updated: 5/5/2026

Supported Sensors: Continuous Assessment, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

Vendor

Vendor Severity: Important

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 5.8

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C

CVSS Score Source: CVE-2026-27857

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:redhat:enterprise_linux:9, p-cpe:/a:redhat:enterprise_linux:dovecot-pgsql, p-cpe:/a:redhat:enterprise_linux:dovecot-mysql, p-cpe:/a:redhat:enterprise_linux:dovecot-pigeonhole, p-cpe:/a:redhat:enterprise_linux:dovecot, p-cpe:/a:redhat:enterprise_linux:dovecot-devel

Required KB Items: Host/local_checks_enabled, Host/RedHat/release, Host/RedHat/rpm-list, Host/cpu

Exploit Ease: No known exploits are available

Patch Publication Date: 5/5/2026

Vulnerability Publication Date: 3/27/2026

Reference Information

CVE: CVE-2025-59032, CVE-2026-27857, CVE-2026-27858

CWE: 229, 770

RHSA: 2026:13857

Detections

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