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CVE-2026-52687

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.

拥有有效凭证的攻击者可以选择一种在解压状态需要消耗大量内存的 IMAP 连接压缩算法，并打开多个此类连接。仅需少量连接即可达到进程的内存上限，从而导致进程终止及其处理的所有连接断开，可能引起 IMAP 服务性能下降或服务中断（DoS）。建议禁用 IMAP 压缩功能；或者限制单个 imap-login 进程处理的连接数量（但这对性能有一定影响）。请升级到不受影响的版本。目前尚未发现公开的利用方式。

CVSS 6.5 · Medium

Possible ATT&CK Techniques 1 AI

T1499 · Endpoint Denial of Service
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I. Basic Information for CVE-2026-52687

Vulnerability Information
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Vulnerability Title
N/A
Source: CVE Program / CVE List V5
Vulnerability Description
An attacker that has valid credentials can select a compression algorithm for the IMAP connection whose decompression state requires a large amount of memory, and open several such connections. The memory limit of the process is reached with only a few connections, terminating the process and all connections it handles, which can cause degradation or denial of service for IMAP. Disable IMAP compression. Alternatively limit the number of connections handled by a single imap-login process, though this has a performance impact. 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: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 2.3.11 ~ 2.3.22.2 -
Open-Xchange GmbH OX Dovecot CE 2.3.11 ~ 2.4.5 -

II. Public POCs for CVE-2026-52687

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III. Intelligence Information for CVE-2026-52687

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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-2026-40014 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-2026-40019 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-2026-33607 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 product: OX Dovecot Pro
Same vendor: Open-Xchange GmbH
Same weakness: CWE-400

V. Comments for CVE-2026-52687

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