CVE-2026-42391
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.
一个未认证的攻击者可以在登录之前发送带有大量参数的 IMAP ID 命令，导致内存和 CPU 使用量不成比例地增长。由于内存不足的处理机制，登录进程可能会被终止，这也会终止由同一进程处理的所有其他连接。这可能导致 IMAP 登录的性能下降或拒绝服务。建议限制单个 imap-login 进程处理的连接数量，但这会对性能产生一定影响。请更新到不受影响的版本。目前尚无公开可用的利用程序。
Possible ATT&CK Techniques 1 AI
T1499 · Endpoint Denial of Service
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I. Basic Information for CVE-2026-42391
Vulnerability Information
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Vulnerability Title
N/A
Source: CVE Program / CVE List V5
Vulnerability Description
An unauthenticated attacker can send an IMAP ID command with a very large number of parameters before logging in, which causes memory and CPU usage to grow disproportionately. The login process can be terminated by the out-of-memory handling, which also terminates all other connections handled by the same process. This can cause degradation or denial of service for IMAP logins. Limit the number of connections handled by a single imap-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: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-2026-42391
| # | 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-2026-27852 | 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-2026-40019 | 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 weakness: CWE-400
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CVE-2026-82261
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CVE-2026-82256
SvelteKit before 2.69.1 Denial of Service via Remote Form -
CVE-2026-82235
filebrowser through 2.63.23 Denial of Service via named pipe -
CVE-2026-52687
Dovecot IMAP压缩算法致拒绝服务
V. Comments for CVE-2026-42391
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