CVE-2026-33604
dovecot: Dovecot: SMTP smuggling vulnerability allows spoofed email injection
Severity
ModerateRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · August 28, 2026
Updated · September 1, 2026
Description
A flaw was found in Dovecot. A remote attacker can exploit this by crafting a message with a specific line ending. If Dovecot relays this message, it can bypass security protections, allowing the attacker to inject spoofed email into a vulnerable downstream mail server. This vulnerability is related to SMTP (Simple Mail Transfer Protocol) smuggling.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
CVSS / CWE
CVSS 3.1 · 5.9CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
CWE-93 · Improper Neutralization of CRLF Sequences ('CRLF Injection')