CVE-2026-27857

A flaw was found in dovecot. An unauthenticated and remote attacker can send a specially crafted "NOOP" command containing numerous open and close parentheses without a command-ending line feed, causing the server to allocate an excessive amount of memory, resulting in a denial of service.

This flaw allows an unauthenticated and remote attacker to cause a denial of service via a specially crafted "NOOP" command. Due to this reason, this vulnerability has been rated with an important severity.

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.

Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update the affected package as soon as possible.