CVE-2026-61911 PUBLISHED

Assigner: mitre
Reserved: 13.07.2026 Published: 09.09.2026 Updated: 09.09.2026

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.

Metrics

CVSS 3.1

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
CVSS Score: 4.3

Attack Vector	Network	Scope	Unchanged
Attack Complexity	Low	Confidentiality Impact	Low
Privileges Required	Low	Integrity Impact	None
User Interaction	None	Availability Impact	None

CVSS 3.1

Product Status

Vendor	cyrusimap
Product	Cyrus IMAP
Versions	Default: unaffected affected from 0 to 3.8.8 (excl.) affected from 3.9.0 to 3.10.4 (excl.) affected from 3.11.0 to 3.12.4 (excl.)

References

Problem Types

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