CVE-2026-40590— FreeScout's Customer AJAX Create Modifies Hidden Existing Customer
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I. Basic Information for CVE-2026-40590
Vulnerability Information
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Vulnerability Title
FreeScout's Customer AJAX Create Modifies Hidden Existing Customer
Source: NVD (National Vulnerability Database)
Vulnerability Description
FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.214, the Change Customer modal exposes a “Create a new customer” flow via POST /customers/ajax with action=create. Under limited visibility, the endpoint drops unique-email validation. If the supplied email already belongs to a hidden customer, Customer::create() reuses that hidden customer object and fills empty profile fields from attacker-controlled input. Version 1.8.214 fixes the vulnerability.
Source: NVD (National Vulnerability Database)
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
Source: NVD (National Vulnerability Database)
Vulnerability Type
通过用户控制密钥绕过授权机制
Source: NVD (National Vulnerability Database)
Vulnerability Title
FreeScout 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
FreeScout是FreeScout公司的一个使用 PHP（Laravel 框架）构建的超轻量级且功能强大的免费开源帮助台和共享收件箱。 FreeScout 1.8.214之前版本存在安全漏洞，该漏洞源于在有限可见性下，POST /customers/ajax端点中的action=create流程会丢弃唯一电子邮件验证，可能导致如果提供的电子邮件已属于隐藏客户，Customer::create会重用该隐藏客户对象并用攻击者控制的输入填充空个人资料字段。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| freescout-help-desk | freescout | < 1.8.214 | - |
II. Public POCs for CVE-2026-40590
| # | POC Description | Source Link | Shenlong Link |
|---|
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Same Patch Batch · freescout-help-desk · 2026-04-21 · 20 CVEs total
| CVE-2026-41193 | 9.1 CRITICAL | FreeScout has Zip Slip path traversal in module installation that allows arbitrary file wr |
| CVE-2026-40569 | 9.0 CRITICAL | FreeScout's Mass Assignment in Mailbox Connection Settings Enables Silent Email Exfiltrati |
| CVE-2026-40568 | 8.5 HIGH | FreeScout Vulnerable to XSS via Mailbox Signature Due to Incomplete HTML Sanitization |
| CVE-2026-40497 | 8.1 HIGH | FreeScout Vulnerable to CSS Injection via Stored Style Tag in Mailbox Signature (CSRF Toke |
| CVE-2026-40589 | 7.6 HIGH | FreeScout has Customer Edit Cross-Mailbox Email Takeover |
| CVE-2026-41190 | 7.1 HIGH | FreeScout has assigned-only visibility bypass via save_draft that allows hidden conversati |
| CVE-2026-41189 | 7.1 HIGH | FreeScout has assigned-only visibility bypass that allows editing hidden customer-authored |
| CVE-2026-41191 | 7.1 HIGH | FreeScout's signature only mailbox permission allows unauthorized mailbox chat setting cha |
| CVE-2026-40591 | 7.1 HIGH | FreeScout: Improper Authorization in Phone Conversation Creation Enables Cross-Mailbox Hid |
| CVE-2026-41192 | 7.1 HIGH | FreeScout's client-controlled attachment IDs allow deletion of existing conversation attac |
| CVE-2026-40565 | 6.1 MEDIUM | FreeScout has Stored XSS / CSS Injection via linkify() — Unescaped URL in Anchor href |
| CVE-2026-40592 | 5.9 MEDIUM | FreeScout's cross-user undo reply allows mailbox peers to recall another agent's outbound |
| CVE-2026-40567 | 5.8 MEDIUM | FreeScout has HTML Injection in Outgoing Emails via Unsanitized Customer Name in Signature |
| CVE-2026-41194 | 5.4 MEDIUM | FreeScout's Mailbox OAuth disconnect uses a state-changing GET and is CSRFable |
| CVE-2026-41183 | 4.3 MEDIUM | FreeScout allows non-folder conversation queries to disclose assigned-only hidden conversa |
| CVE-2026-40566 | 4.1 MEDIUM | FreeScout vulnerable to SSRF via IMAP/SMTP Connection Test Endpoints |
| CVE-2026-40570 | FreeScout's Missing Authorization in load_customer_info Allows Any Authenticated User to A | |
| CVE-2026-40498 | FreeScout has Authentication Bypass and Information Disclosure in SystemController via /sy | |
| CVE-2026-40496 | FreeScout has Predictable Attachment Token that Allows Unauthenticated Private File Downlo |
IV. Related Vulnerabilities
Same product: freescout
- CVE-2026-41906
FreeScout: Conversation Change-Customer Cross-Mailbox Author - CVE-2026-41905
FreeScout vulnerable to SSRF via Helper::sanitizeRemoteUrl: - CVE-2026-41904
FreeScout Stored XSS vulnerability in mailbox auto-reply: pa - CVE-2026-41902
FreeScout's user invitation hash never expires: permanent un - CVE-2026-41903
FreeScout IDOR Vulnerability: PERM_EDIT_USERS allows modifyi
Same vendor: freescout-help-desk
- CVE-2026-41906
FreeScout: Conversation Change-Customer Cross-Mailbox Author - CVE-2026-41905
FreeScout vulnerable to SSRF via Helper::sanitizeRemoteUrl: - CVE-2026-41904
FreeScout Stored XSS vulnerability in mailbox auto-reply: pa - CVE-2026-41902
FreeScout's user invitation hash never expires: permanent un - CVE-2026-41903
FreeScout IDOR Vulnerability: PERM_EDIT_USERS allows modifyi
Same weakness: CWE-639
- CVE-2026-8196
JeecgBoot mLogin Endpoint LoginController.java authorization - CVE-2026-42291
SysReptor: Read-write access to personal notes by sharing-li - CVE-2026-44400
MailEnable Enterprise Premium < 10.55 Authorization Bypass v - CVE-2026-42279
solidtime: Time entry update endpoint allows cross-organizat - CVE-2026-42277
Onyx: IDOR in /chat/file/{file_id} allows any authenticated
V. Comments for CVE-2026-40590
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