What is CVE-2026-61911?

CVE-2026-61911 is a medium-severity vulnerability in Cyrusimap Cyrus Imap, classified under Exposure of Sensitive System Information to an Unauthorized Control Sphere. CVSS score: 4.3/10. Published 2026-09-09.

How severe is CVE-2026-61911?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Vulnerability in Cyrusimap Cyrus Imap

CVE-2026-61911

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.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.

Affected products

Cyrusimap Cyrus Imap
N/a

Weakness classification (CWE)

CWE-497 — Exposure of Sensitive System Information to an Unauthorized Control Sphere

References

Frequently asked questions

What is CVE-2026-61911?: CVE-2026-61911 is a medium-severity vulnerability in Cyrusimap Cyrus Imap, classified under Exposure of Sensitive System Information to an Unauthorized Control Sphere. CVSS score: 4.3/10. Published 2026-09-09.
How severe is CVE-2026-61911?: Medium severity. CVSS v3 base score is 4.3 out of 10.