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CVE-2026-40020

Quick assessment

Affected
Open-Xchange GmbH OX Dovecot Pro
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Open-Xchange OX Dovecot Pro是德国Open-Xchange公司的一个邮件存储与投递系统。 Open-Xchange OX Dovecot Pro存在访问控制错误漏洞，该漏洞源于IMAP SETACL命令可注入anyone权限到用户dovecot-acl文件，即使imap_acl_allow_anyone=no设置，导致文件夹被垃圾邮件发送给所有用户。

CVSS 3.1 · Low EPSS 0.29% · P20

Affected Version Matrix 1

VendorProduct Version RangeStatus
Open-Xchange GmbH OX Dovecot Pro ≤ 2.3.0 affected
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I. Basic Information for CVE-2026-40020

Vulnerability Information
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Vulnerability Title
N/A
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L
Source: CVE Program / CVE List V5
Vulnerability Type
访问控制不恰当
Source: CVE Program / CVE List V5
Vulnerability Title
Open-Xchange OX Dovecot Pro 访问控制错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Open-Xchange OX Dovecot Pro是德国Open-Xchange公司的一个邮件存储与投递系统。 Open-Xchange OX Dovecot Pro存在访问控制错误漏洞，该漏洞源于IMAP SETACL命令可注入anyone权限到用户dovecot-acl文件，即使imap_acl_allow_anyone=no设置，导致文件夹被垃圾邮件发送给所有用户。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Open-Xchange GmbH OX Dovecot Pro 0 ~ 2.3.0 -

II. Public POCs for CVE-2026-40020

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III. Intelligence Information for CVE-2026-40020

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Vendor Advisories for CVE-2026-40020 (1)

Same Patch Batch · Open-Xchange GmbH · 2026-05-12 · 5 CVEs total

CVE-2026-27851 7.4 HIGH Open-Xchange OX Dovecot Pro 安全漏洞
CVE-2026-33603 6.8 MEDIUM Open-Xchange OX Dovecot Pro 安全漏洞
CVE-2026-40016 5.3 MEDIUM Open-Xchange OX Dovecot Pro 资源管理错误漏洞
CVE-2026-42006 4.3 MEDIUM Open-Xchange OX Dovecot Pro 资源管理错误漏洞

IV. Related Vulnerabilities

Same product: OX Dovecot Pro
Same vendor: Open-Xchange GmbH
Same weakness: CWE-284

V. Comments for CVE-2026-40020

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