CVE-2026-61907 Missing authorization in Cyrus IMAP
An authenticated user can bypass ACLs to insert mail into other users' inboxes via JMAP snooze functionality in Cyrus IMAP.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-61907?
CVE-2026-61907 is a medium-severity missing authorization vulnerability in cyrusimap Cyrus IMAP, published on 9 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
An issue was discovered in Cyrus IMAP before 3.12.4. JMAP snooze bypasses the destination-mailbox ACL. An authenticated user with insert permissions on another user's snoozed mailbox could cause insertion of mail to that user's inbox, or any other of their mailboxes whose id was known to the user, despite having no insert permissions to the target mailbox.
Weakness: CWE-863
Which versions are affected by CVE-2026-61907?
How do I fix CVE-2026-61907?
Upgrade to a fixed version.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-61907 being exploited?
There is no known exploitation of CVE-2026-61907 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-61907, GHSA-245j-3rxm-cqmg, UBUNTU-CVE-2026-61907.