Home/CVE/Attacker can use the IMAP SETACL command to inject the anyone permission to user's dovecot-acl file even if imap_acl_all
CVE

CVE-2026-40020

Attacker can use the IMAP SETACL command to inject the anyone permission to user's dovecot-acl file even if imap_acl_all

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.

LOW · CVSS 3.1 EPSS 0.00014
Monitor
  • No active-exploitation, high-EPSS, or public-exploit signals - routine patching cadence
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-284Improper Access Control
▤

Affected Products & Versions

2
dovecot< 2.4.4
open-xchange dovecot< 3.1.5
▣

Scoring & Timeline

3.1
LOW · CVSS v3.1 · security@open-xchange.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD12 May 2026 · 02:17 PM
CVSS VectorCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
no
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
⚑

Vendor Advisories

2
usnUSN-8365-1
suse-csafopenSUSE-SU-2026:10766-1
🔗

References & Sources

1
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0002.jsonVendor Advisory
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