CVE-2026-61911

MEDIUM

4.3

CVSS Score

Published: September 9, 2026 at 12:00 AM UTC

Updated: September 16, 2026 at 03:37 PM UTC

3 products affected across 2 vendorsCyrusimapImapCyrus IMAP

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Severity

MEDIUM4.3

Exploit prediction

EPSS 0.2%

SSVC

No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Imap · Cyrus

95%

v < 3.8.83.11.0 ≤ v < 3.12.43.9.0 ≤ v < 3.10.4

Affected range stops below 3.10.4, so it looks safe — our inference, not a vendor statement

Affected range stops below 3.12.4, so it looks safe — our inference, not a vendor statement

Affected range stops below 3.8.8, so it looks safe — our inference, not a vendor statement

Cyrusimap · Cyrusimap

95%

v < 3.8.83.11.0 ≤ v < 3.12.43.9.0 ≤ v < 3.10.4

Affected range stops below 3.10.4, so it looks safe — our inference, not a vendor statement

Affected range stops below 3.12.4, so it looks safe — our inference, not a vendor statement

Affected range stops below 3.8.8, so it looks safe — our inference, not a vendor statement

Cyrus IMAP · Cyrusimap

60%

v < 3.8.83.11.0 ≤ v < 3.12.43.9.0 ≤ v < 3.10.43.11.0 3.9.0

Affected range stops below 3.10.4, so it looks safe — our inference, not a vendor statement

Affected range stops below 3.12.4, so it looks safe — our inference, not a vendor statement

Affected range stops below 3.8.8, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

References (4)

Product

Source: cverecord

https://cyrusimap.org

Release Notes

Source: cverecord

https://www.cyrusimap.org/3.12/imap/download/release-notes/3.12/x/3.12.4.html

Release Notes

Source: cverecord

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

Release Notes

Source: cverecord

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

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

4.3MEDIUMmitre

Attack Vector: NETWORK
Complexity: LOW
Privileges: LOW
User Interaction: NONE
Scope: UNCHANGED
Confidentiality: LOW
Integrity: NONE
Availability: NONE

Vector?

Quick Info

StatusANALYZED

CWE

CWE-497

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