SB2026052013 - Red Hat Enterprise Linux 8 update for dovecot
Published: May 20, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 3 vulnerabilities.
1) 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.
2) 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.
3) 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.