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CVE-2026-40017

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 2.3.0版本至2.3.22.2之前版本、3.0.0版本至3.0.7之前版本和3.1.0版本至3.1.6之前版本，以及OX Dovecot CE 2.3.0版本至2.4.5之前版本存在资源管理错误漏洞，该漏洞源于消息头值在内部哈希表中发生碰撞，导致IMAP THREAD命令消耗过多CPU，可能造成服务降级或拒绝服务。

CVSS 6.5 · Medium EPSS 0.33% · P25

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-2026-40017

Vulnerability Information
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Vulnerability Title
N/A
Source: CVE Program / CVE List V5
Vulnerability Description
An attacker that can send mail to a user can craft a message header whose values are chosen to collide in an internal hash table, which makes the IMAP THREAD command consume CPU disproportionate to the size of the message. This is a separate issue from CVE-2026-40014 and is not addressed by that fix. Whenever a mail client issues a THREAD command on the affected mailbox, this can cause degradation or denial of service for IMAP. Monitor system for abnormal CPU usage, kill the offending process and remove the offending message from the affected mailbox. 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:R/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 2.3.0版本至2.3.22.2之前版本、3.0.0版本至3.0.7之前版本和3.1.0版本至3.1.6之前版本，以及OX Dovecot CE 2.3.0版本至2.4.5之前版本存在资源管理错误漏洞，该漏洞源于消息头值在内部哈希表中发生碰撞，导致IMAP THREAD命令消耗过多CPU，可能造成服务降级或拒绝服务。
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-2026-40017

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III. Intelligence Information for CVE-2026-40017

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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-2026-42391 7.5 HIGH 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-2026-73209 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-2026-42008 4.3 MEDIUM Open-Xchange Dovecot Pro 授权问题漏洞
CVE-2026-33607 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-2026-42395 4.3 MEDIUM Open-Xchange Dovecot Pro 资源管理错误漏洞

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-2026-40017

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