SB2026061751 - Red Hat Enterprise Linux 7 Extended Lifecycle Support update for dovecot

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Main Vulnerability Database SB2026061751

SB2026061751 - Red Hat Enterprise Linux 7 Extended Lifecycle Support update for dovecot

Published: June 17, 2026

Security Bulletin ID SB2026061751
CSH Severity
High
Patch available
YES
Number of vulnerabilities 4
Exploitation vector Remote access
Highest impact Denial of service

Breakdown by Severity

High 25% Medium 75%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 4 vulnerabilities.


1) Improper Authentication (CVE-ID: CVE-2026-27856)

CWE-ID: CWE-287 - Improper Authentication

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Amber


The vulnerability allows a remote attacker to bypass authentication.

The vulnerability exists due to improper authentication in doveadm credentials verification when comparing provided credentials. A remote attacker can perform timing oracle attack to bypass authentication.


2) Improper input validation (CVE-ID: CVE-2025-59032)

CWE-ID: CWE-20 - Improper input validation

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to improper input validation in Pigeonhole ManageSieve service when processing SASL AUTHENTICATE command. A remote attacker can send a specially crafted request using literal as SASL initial response to cause a denial of service.

The ManageSieve service crashes and becomes unavailable for other users.


3) Resource exhaustion (CVE-ID: CVE-2026-27858)

CWE-ID: CWE-400 - Resource exhaustion

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to uncontrolled resource consumption in managesieve-login service when processing pre-authentication data. A remote attacker can send a specially crafted message before authentication to cause a denial of service.


4) Resource exhaustion (CVE-ID: CVE-2026-27857)

CWE-ID: CWE-400 - Resource exhaustion

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L/E:U/U:Green


The vulnerability allows a remote user to cause a denial of service.

The vulnerability exists due to uncontrolled resource consumption in imap-login process when handling malformed NOOP commands. A remote user can send a specially crafted command with excessive parentheses to cause a denial of service.


Remediation

Install update from vendor's website.

References