CVE-2026-47082 cyrusimap CVE debrief

Who should care

Users of Cyrus IMAP through 3.12.2 should review and apply patches to prevent unauthorized access. Additionally, administrators should restrict access to sensitive mailboxes and monitor for suspicious activity, particularly focusing on Sieve script usage and mailbox permissions.

Technical summary

The vacation 'fcc' feature in Cyrus IMAP through 3.12.2 skips the destination-mailbox ACL, allowing users to deliver vacation auto-reply copies into any mailbox they can name, regardless of their insert permissions on the destination mailbox. This could potentially lead to unauthorized access. The issue is particularly concerning for users with Sieve scripts that utilize the :fcc feature, as it could enable delivery of auto-reply copies to unintended mailboxes.

Defensive priority

Medium priority due to CVSS score of 5.4 and potential for unauthorized access through the exploitation of the vacation 'fcc' feature.

Recommended defensive actions

• Review and apply patches for Cyrus IMAP 3.12.2 or later
• Restrict access to sensitive mailboxes
• Monitor for suspicious activity
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.
• Review compensating controls for exposed systems while remediation is scheduled and verified.
• Check relevant monitoring, detection, and logs for exposed assets that need extra review.
• Track exceptions, retest remediated assets, and close the item only after evidence is documented.

Evidence notes

Evidence is limited; verify affected versions and apply patches. The CVE record was published on 2026-07-16T19:16:48.713Z and has not been modified since then. Users should review the official CVE record and NVD details for further information. Additional verification tasks include checking for Sieve script usage of the :fcc feature and assessing mailbox permissions.

Official resources