Description
An issue was discovered in cyrus-imapd in Cyrus IMAP through 3.12.2. GENURLAUTH-issued tokens can bypass ACLs. Any authenticated user could mint a URLAUTH token (via the GENURLAUTH command) for any mailbox they could name, even without read access on it. This would allow reading mail from mailboxes despite having no granted permissions.
References2
Metrics
- CVSS 3.1
-
3.5
LOW
Score source: CNA
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N - EPSS — exploit probability
- 0% percentile: 19 · as of 15 November 2026
- CWE
- CWE-863
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.