CVE-2026-61911

medium

Description

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.

References

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

https://cyrusimap.org

Details

Source: Mitre, NVD

Published: 2026-09-09

Updated: 2026-09-10

Risk Information

CVSS v2

Base Score: 4

Vector: CVSS2#AV:N/AC:L/Au:S/C:P/I:N/A:N

Severity: Medium

CVSS v3

Base Score: 4.3

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

Severity: Medium

EPSS

EPSS: 0.00217