CVE-2026-61911

A flaw was found in cyrus-imapd. An authenticated user could install a Sieve script to determine if another user's private mailbox exists. This is achieved by observing the behavior of the fileinto branch during Local Mail Transfer Protocol (LMTP) delivery. Additionally, this method could allow the user to read the values of shared mailbox annotations, leading to information disclosure.

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 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.