CVE-2026-33263
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，该漏洞源于文件描述符处理不当，当mail_max_userip_connections达到限制时可能导致epoll()错误崩溃，进而导致用户无法发送消息或重复发送消息。
Possible ATT&CK Techniques 1 AI
T1025 · Data from Removable MediaAffected Version Matrix 4
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| 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-2026-33263
Vulnerability Information
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Vulnerability Title
N/A
Source: CVE Program / CVE List V5
Vulnerability Description
When mail_max_userip_connections is set (default 10) and reached, submission-login can crash with epoll() panic caused by file descriptor handling issues. If running in high-security mode (default for community releases), only the new submission connection gets terminated. If running in high-performance mode (default for Pro releases), all connections handled by the submission-login process will be terminated. The crashes can cause failure for user to send a message, or it can cause duplicate messages to be sent. If TLS is not used (in the backend server processing the submission), duplicate deliveries cannot happen, because the crash can only happen at AUTH stage. Limit the number of connections handled by single submission-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:L/UI:N/S:U/C:N/I:N/A:L
Source: CVE Program / CVE List V5
Vulnerability Type
将文件描述符暴露给不受控制的范围(文件描述符泄露)
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，该漏洞源于文件描述符处理不当，当mail_max_userip_connections达到限制时可能导致epoll()错误崩溃，进而导致用户无法发送消息或重复发送消息。
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-2026-33263
| # | POC Description | Source Link | Shenlong Link |
|---|
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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-2026-33605 | 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-2026-40018 | 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-2026-73209 | 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-2026-33604 | 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-2026-40015 | 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 → →
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