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CVE-2026-40019

Quick assessment

Affected
Open-Xchange GmbH OX Dovecot CE
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.

未经身份验证的攻击者可以向 ManageSieve 登录进程发送一个截断的带引号参数，导致其陷入无限循环，持续消耗 CPU 资源。这可能导致 Sieve 脚本管理服务的性能下降或服务中断，频繁的重复连接甚至可能耗尽服务器上的所有可用 CPU。建议监控系统是否出现异常 CPU 占用，并终止出现问题的进程。将 ManageSieve 服务的网络访问权限限制为可信客户端。升级到不受影响的版本。目前没有公开可用的漏洞利用程序（exploit）。

CVSS 5.9 · Medium
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I. Basic Information for CVE-2026-40019

Vulnerability Information
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Vulnerability Title
N/A
Source: CVE Program / CVE List V5
Vulnerability Description
An unauthenticated attacker can send a truncated quoted argument to the ManageSieve login process, which makes it spin in an infinite loop consuming CPU. This can cause degradation or denial of service for Sieve script management, and repeated connections can consume all available CPU on the server. Monitor system for abnormal CPU usage and kill the offending process. 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:H/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 CE 2.4.3 ~ 2.4.5 -

II. Public POCs for CVE-2026-40019

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III. Intelligence Information for CVE-2026-40019

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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-2026-33605 7.5 HIGH ManageSieve 认证前畸形命令崩溃DoS漏洞
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-2026-40014 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-2026-73209 6.5 MEDIUM IMAP服务栈溢出拒绝服务漏洞
CVE-2026-33604 5.9 MEDIUM Dovecot SMTP邮件走私漏洞
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-2026-33607 4.3 MEDIUM IMAP LIST命令致CPU耗尽或DoS
CVE-2026-42395 4.3 MEDIUM OpenSSH可信代理NUL字节致登录进程崩溃
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-2026-42008 4.3 MEDIUM Dovecot 受信代理认证字段注入漏洞

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

IV. Related Vulnerabilities

Same vendor: Open-Xchange GmbH
Same weakness: CWE-400

V. Comments for CVE-2026-40019

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