CVE-2026-61911: CWE-497 Exposure of Sensitive System Information to an Unauthorized Control Sphere in cyrusimap Cyrus IMAP
Affects cyrusimap Cyrus IMAPSource CVE Database V5
Not known to be exploited · CVSS 4.3 Medium · fixed in 3.12.4 : update cyrusimap Cyrus IMAP when convenient.
Data as of 10/25/2026, 04:40:13 UTC
- Exploitation
Not in CISA KEV, no exploitation reported
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 11% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 3.12.4
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:NWhat to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| cyrusimapCyrus IMAP | Affected
| Fixed in
|
AI-suggested
A fix is available in Cyrus IMAP version 3.12.4. Users should upgrade to version 3.12.4 or later to remediate this vulnerability. No vendor advisory was provided to indicate alternative mitigations or that no action is required.
Description
CVE-2026-61911 is a medium severity vulnerability in Cyrus IMAP before version 3.12.4. It allows an authenticated user to leverage a Sieve script to detect the existence of another user's private mailbox or read shared mailbox annotations by observing LMTP delivery behavior. This vulnerability exposes sensitive system information but does not permit modification or denial of service.
Impact
The vulnerability exposes sensitive system information about mailbox existence and shared mailbox annotations to authenticated users. This information disclosure could facilitate further reconnaissance by an attacker but does not directly enable data modification or denial of service.
Weaknesses
- CWE-497Exposure of Sensitive System Information to an Unauthorized Control Sphere (opens in a new tab)
Base weaknessOWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product does not properly prevent sensitive system-level information from being accessed by unauthorized actors who do not have the same level of access to the underlying system as the product does.