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CVE-2026-40020

Published: May 12, 2026Updated: May 18, 2026 Sources: CVE List NVDCWE-284
3.1LOW
NVD MITRE
EPSS Score
0.3%
Top 80.6%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
OpenVAS

Description

Attacker can use the IMAP SETACL command to inject the anyone permission to user's dovecot-acl file even if imap_acl_allow_anyone=no. This causes folders to be spammed to all users. The impact is limited to being able to spam folders to other users, no unexpected access is gained. Install to fixed version. No publicly available exploits are known.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:HPR:LUI:NS:UC:NI:NA:L
Exploitability
AV:NAttack Vector
Network
AC:HAttack Complexity
High
PR:LPrivileges Required
Low
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:LAvailability
Low
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Weaknesses

CWE-284NVD-CWE-noinfo

Affected Products

Open-Xchange GmbH
commercial·DEaka open-xchange
OX Dovecot Pro
Communications
dovecot
oss-projectaka pigeonhole
dovecotOn-premWeb App
Communications / email-server-client
open-xchange
commercial·DEaka ox, open-xchange gmbh
dovecot
Communications

Exploitability

Official Patch Available
Is your org exposed to CVE-2026-40020?We can run the check for you — a free external exposure review, no install. Check my exposure

References

https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0002.json
documentation.open-xchange.com

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