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CVE-2026-42391

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 Dovecot Pro是德国Open-Xchange公司的一个邮件服务器软件。 Open-Xchange Dovecot Pro 2.3.22.2之前版本、3.0.7之前版本和3.1.6之前版本，以及OX Dovecot CE 2.4.5之前版本存在资源管理错误漏洞，该漏洞源于IMAP ID命令处理不当，可能导致未经验证的攻击者在登录前发送包含大量参数的IMAP ID命令，造成内存和CPU使用量不成比例增长，从而导致IMAP登录降级或拒绝服务。

CVSS 7.5 · High EPSS 0.45% · P37

Possible ATT&CK Techniques 1 AI

T1499 · Endpoint Denial of Service

Affected Version Matrix 4

VendorProduct Version RangeStatus
Open-Xchange GmbH OX Dovecot CE 2.3.0< 2.4.5 affected
Open-Xchange GmbH OX Dovecot Pro 2.3.0< 2.3.22.2 affected
3.0.0< 3.0.7 affected
3.1.0< 3.1.6 affected
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I. Basic Information for CVE-2026-42391

Vulnerability Information
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Vulnerability Title
N/A
Source: CVE Program / CVE List V5
Vulnerability Description
An unauthenticated attacker can send an IMAP ID command with a very large number of parameters before logging in, which causes memory and CPU usage to grow disproportionately. The login process can be terminated by the out-of-memory handling, which also terminates all other connections handled by the same process. This can cause degradation or denial of service for IMAP logins. Limit the number of connections handled by a single imap-login process. This has a performance impact though. Update to non-vulnerable version. No publicly available exploits are known.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
未加控制的资源消耗(资源穷尽)
Source: CVE Program / CVE List V5
Vulnerability Title
Open-Xchange Dovecot Pro 资源管理错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Open-Xchange Dovecot Pro是德国Open-Xchange公司的一个邮件服务器软件。 Open-Xchange Dovecot Pro 2.3.22.2之前版本、3.0.7之前版本和3.1.6之前版本，以及OX Dovecot CE 2.4.5之前版本存在资源管理错误漏洞，该漏洞源于IMAP ID命令处理不当，可能导致未经验证的攻击者在登录前发送包含大量参数的IMAP ID命令，造成内存和CPU使用量不成比例增长，从而导致IMAP登录降级或拒绝服务。
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 2.3.0 ~ 2.3.22.2 -
Open-Xchange GmbH OX Dovecot CE 2.3.0 ~ 2.4.5 -

II. Public POCs for CVE-2026-42391

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III. Intelligence Information for CVE-2026-42391

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Same Patch Batch · Open-Xchange GmbH · 2026-08-28 · 25 CVEs total

CVE-2026-42007 9.1 CRITICAL Open-Xchange Dovecot Pro 资源管理错误漏洞
CVE-2026-27852 7.5 HIGH Open-Xchange Dovecot Pro 资源管理错误漏洞
CVE-2026-33605 7.5 HIGH Open-Xchange Dovecot Pro 资源管理错误漏洞
CVE-2026-40018 7.4 HIGH Open-Xchange Dovecot Pro SQL注入漏洞
CVE-2026-73208 7.4 HIGH Open-Xchange Dovecot Pro 授权问题漏洞
CVE-2026-52687 6.5 MEDIUM Open-Xchange Dovecot Pro 资源管理错误漏洞
CVE-2026-40014 6.5 MEDIUM Open-Xchange Dovecot Pro 资源管理错误漏洞
CVE-2026-40017 6.5 MEDIUM Open-Xchange Dovecot Pro 资源管理错误漏洞
CVE-2026-73209 6.5 MEDIUM Open-Xchange Dovecot Pro 资源管理错误漏洞
CVE-2026-33604 5.9 MEDIUM Open-Xchange Dovecot Pro 安全漏洞
CVE-2026-40019 5.9 MEDIUM Open-Xchange GmbH OX Dovecot CE 资源管理错误漏洞
CVE-2026-40205 5.9 MEDIUM Open-Xchange Dovecot Pro 授权问题漏洞
CVE-2026-33606 4.8 MEDIUM Open-Xchange Dovecot Pro 输入验证错误漏洞
CVE-2026-33607 4.3 MEDIUM Open-Xchange Dovecot Pro 资源管理错误漏洞
CVE-2026-42395 4.3 MEDIUM Open-Xchange Dovecot Pro 资源管理错误漏洞
CVE-2026-33263 4.3 MEDIUM Open-Xchange Dovecot Pro 资源管理错误漏洞
CVE-2026-40015 4.3 MEDIUM Open-Xchange Dovecot Pro 缓冲区错误漏洞
CVE-2026-40013 4.3 MEDIUM Open-Xchange Dovecot Pro 缓冲区错误漏洞
CVE-2026-42392 4.3 MEDIUM Open-Xchange Dovecot Pro 信息泄露漏洞
CVE-2026-42008 4.3 MEDIUM Open-Xchange Dovecot Pro 授权问题漏洞

Showing top 20 of 25 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: OX Dovecot Pro
Same vendor: Open-Xchange GmbH
Same weakness: CWE-400

V. Comments for CVE-2026-42391

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