CVE-2026-61911

4.3 mediumEPSS 0.2%

Medium (4.3) in cyrus imap. EPSS 0.2% chance of exploitation in the next 30 days.

An issue was discovered in Cyrus IMAP before 3.12.4. There is a Sieve mailbox existence oracle. An authenticated user could install a Sieve script that probed whether another user's private mailbox existed, or read the value of shared mailbox annotations, by observing which fileinto branch fired during LMTP delivery.

Severity

CVSS 3.1

4.3 medium

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

EPSS: 0.2% chance of exploitation in the next 30 days; higher than 12% of CVEs (scores of 2026-11-01)
CWE: CWE-497
Published: 2026-09-09
Modified: 2026-09-16
Record from: the NVD, synced 2026-10-19

Affected

cyrus:imap

References

https://cyrusimap.org
https://www.cyrusimap.org/3.12/imap/download/release-notes/3.10/x/3.10.4.html
https://www.cyrusimap.org/3.12/imap/download/release-notes/3.12/x/3.12.4.html
https://www.cyrusimap.org/3.12/imap/download/release-notes/3.8/x/3.8.8.html

Check your stack JSON