CVE-2026-61911

EUVD-2026-75129
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.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
mitreCNA
4.3 MEDIUM
NETWORK
LOW
LOW
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Base Score
CVSS 3.x
EPSS Score
Percentile: Unknown
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources.
VendorProductVersionSource
cyrusimapcyrus_imap
𝑥
< 3.8.8
CNA
cyrusimapcyrus_imap
3.9.0 ≤
𝑥
< 3.10.4
CNA
cyrusimapcyrus_imap
3.11.0 ≤
𝑥
< 3.12.4
CNA
Common Weakness Enumeration
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