CVE-2026-33604
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.
如果一个攻击者能够促使 Dovecot 转发邮件（例如通过 Sieve 重定向或提交中继），他们可以利用消息体末尾经过精心构造的换行符，绕过防止消息内容被解释为 SMTP 命令的出站保护机制。如果下游邮件服务器尚未修复 SMTP 走私（SMTP smuggling）漏洞，攻击者就可以诱使该服务器将消息体的一部分误认为新的 SMTP 命令，从而实现伪造邮件的注入。该漏洞与 CVE-2023-51764 和 CVE-2023-51766 属于同一漏洞类别。在你能控制的接收邮件服务器上，请确保它们拒绝消息数据中的孤立回车
Possible ATT&CK Techniques 2 AI
T1010 · Application Window Discovery T1030 · Data Transfer Size Limits
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I. Basic Information for CVE-2026-33604
Vulnerability Information
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Vulnerability Title
N/A
Source: CVE Program / CVE List V5
Vulnerability Description
An attacker that can get Dovecot to relay a message, for example through Sieve redirect or submission relay, can use a crafted line ending in the message body to bypass the outbound protection that prevents message content from being interpreted as SMTP commands. A downstream mail server that hasn't yet fixed the SMTP smuggling vulnerability can be tricked into treating part of the message body as new SMTP commands, allowing injection of spoofed email. This is the same vulnerability class as CVE-2023-51764 and CVE-2023-51766. Where you control the receiving mail servers, ensure they reject bare carriage returns in message data. 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:H/PR:N/UI:N/S:U/C:N/I:H/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
不充分的心理学可接受性
Source: CVE Program / CVE List V5
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-2026-33604
| # | POC Description | Source Link | Shenlong Link |
|---|
AI-Generated POC
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Same Patch Batch · Open-Xchange GmbH · 2026-08-28 · 25 CVEs total
| CVE-2026-42007 | 9.1 CRITICAL | OpenWebmail 6.0 及之前版本 内存越界写漏洞 |
| CVE-2026-42391 | 7.5 HIGH | IMAP未认证ID命令引发内存与CPU资源耗尽 |
| CVE-2026-33605 | 7.5 HIGH | ManageSieve 认证前畸形命令崩溃DoS漏洞 |
| CVE-2026-27852 | 7.5 HIGH | Dovecot 特定版本 IMAP 邮件解析内存耗尽 DoS |
| CVE-2026-40018 | 7.4 HIGH | 未知软件：无已知公开利用 |
| CVE-2026-73208 | 7.4 HIGH | Dovecot OAuth2 audience 冒充 scope 导致越权 |
| CVE-2026-52687 | 6.5 MEDIUM | Dovecot IMAP压缩算法致拒绝服务 |
| CVE-2026-73209 | 6.5 MEDIUM | IMAP服务栈溢出拒绝服务漏洞 |
| CVE-2026-40014 | 6.5 MEDIUM | IMAP THREAD命令致高CPU占用，修复指定版本 |
| CVE-2026-40017 | 6.5 MEDIUM | Dovecot特定版本IMAP THREAD命令哈希碰撞DoS漏洞 |
| CVE-2026-40019 | 5.9 MEDIUM | ManageSieve 0.6.1 存在 CPU 耗尽型拒绝服务漏洞 |
| CVE-2026-40205 | 5.9 MEDIUM | OAuth2 令牌校验缺陷，远程验证未强制作用域 |
| CVE-2026-33606 | 4.8 MEDIUM | Dovecot dsync流协议邮件内容注入漏洞 |
| CVE-2026-42008 | 4.3 MEDIUM | Dovecot 受信代理认证字段注入漏洞 |
| CVE-2026-33607 | 4.3 MEDIUM | IMAP LIST命令致CPU耗尽或DoS |
| CVE-2026-33263 | 4.3 MEDIUM | 提交登录模块崩溃：高并发下连接上限触发 epoll 异常 |
| CVE-2026-40015 | 4.3 MEDIUM | IMAP-hibernate越界读致进程崩溃 |
| CVE-2026-40013 | 4.3 MEDIUM | ManageSieve 越界写导致拒绝服务漏洞 |
| CVE-2026-42392 | 4.3 MEDIUM | 该漏洞影响某软件的IMAP URLAUTH功能，版本未知，类型为信息泄露 |
| CVE-2026-42395 | 4.3 MEDIUM | OpenSSH可信代理NUL字节致登录进程崩溃 |
Showing top 20 of 25 CVEs. View all on vendor page → →
IV. Related Vulnerabilities
V. Comments for CVE-2026-33604
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