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CVE-2026-33605

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.

未认证的攻击者可以在认证前发送一条小型畸形命令，导致 ManageSieve 登录进程崩溃。如果系统运行在高安全模式（社区版默认模式），则仅会终止攻击者自身的连接；如果运行在高性能模式（专业版默认模式），则由同一个 managesieve-login 进程处理的所有连接都会被终止。重复执行该攻击会导致 Sieve 脚本管理功能出现拒绝服务（DoS）。建议将 ManageSieve 服务的网络访问限制为仅允许受信任的客户端，并更新到不受影响的版本。目前尚无公开的利用工具或攻击代码。

CVSS 7.5 · High EPSS 0.38% · P30

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-2026-33605

Vulnerability Information
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Vulnerability Title
N/A
Source: CVE Program / CVE List V5
Vulnerability Description
An unauthenticated attacker can crash the ManageSieve login process by sending a small malformed command before authenticating. If running in high-security mode (default for community releases), only the attacker's own connection is terminated. If running in high-performance mode (default for Pro releases), all connections handled by the same managesieve-login process are terminated. Repeating the attack can cause denial of service for Sieve script management. Restrict network access to the ManageSieve service to trusted clients. 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

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-2026-33605

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III. Intelligence Information for CVE-2026-33605

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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-2026-27852 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-2026-33604 5.9 MEDIUM Dovecot SMTP邮件走私漏洞
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 &rarr; →

IV. Related Vulnerabilities

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

V. Comments for CVE-2026-33605

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