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CVE-2026-40020

Published: May 12, 2026Updated: May 18, 2026 Sources: CVE List NVDCWE-284
NVD MITRE
3.1CVSSLOW
EPSS Score
0.3%
Top 80.4%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

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.

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

OX Dovecot ProOpen-Xchange GmbH
On-prem
Enterprise Software / collaboration-groupware
dovecotdovecot
On-premWeb App
Communications / email-server-client
dovecotopen-xchangeCommunications
open-xchange gmbhcommercialDEEnterprise Softwareaka open-xchange
dovecotoss-projectCommunicationsaka dovecot, pigeonhole
open-xchangecommercialDECommunicationsaka open-xchange gmbh, ox

Exploitability

Official Patch Available

References

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

Timeline

Published
May 12, 2026
Last Updated
May 18, 2026

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