CVE-2026-40569— FreeScout's Mass Assignment in Mailbox Connection Settings Enables Silent Email Exfiltration

FreeScout's Mass Assignment in Mailbox Connection Settings Enables Silent Email Exfiltration

FreeScout is a free self-hosted help desk and shared mailbox. Versions prior to 1.8.213 have a mass assignment vulnerability in the mailbox connection settings endpoints of FreeScout (`connectionIncomingSave()` at `app/Http/Controllers/MailboxesController.php:468` and `connectionOutgoingSave()` at line 398). Both methods pass `$request->all()` directly to `$mailbox->fill()` without any field allowlisting, allowing an authenticated admin to overwrite any of the 32 fields in the Mailbox model's `$fillable` array -- including security-critical fields that do not belong to the connection settings form, such as `auto_bcc`, `out_server`, `out_password`, `signature`, `auto_reply_enabled`, and `auto_reply_message`. Validation in `connectionIncomingSave()` is entirely commented out, and the validator in `connectionOutgoingSave()` only checks value formats for SMTP fields without stripping extra parameters. An authenticated admin user can exploit this by appending hidden parameters (e.g., `auto_bcc=attacker@evil.com`) to a legitimate connection settings save request. Because the `auto_bcc` field is not displayed on the connection settings form (it only appears on the general mailbox settings page), the injection is invisible to other administrators reviewing connection settings. Once set, every outgoing email from the affected mailbox is silently BCC'd to the attacker via the `SendReplyToCustomer` job. The same mechanism allows redirecting outgoing SMTP through an attacker-controlled server, injecting tracking pixels or phishing links into email signatures, and enabling attacker-crafted auto-replies -- all from a single HTTP request. This is particularly dangerous in multi-admin environments where one admin can silently surveil mailboxes managed by others, and when an admin session is compromised via a separate vulnerability (e.g., XSS), the attacker gains persistent email exfiltration that survives session expiry. Version 1.8.213 fixes the issue.

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:L

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FreeScout 安全漏洞

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 1.8.213之前版本存在安全漏洞，该漏洞源于邮箱连接设置端点中的connectionIncomingSave和connectionOutgoingSave方法将$request->all直接传递给$mailbox->fill，可能导致经过身份验证的管理员用户覆盖Mailbox模型中的任何可填充字段，包括安全关键字段，从而静默密送邮件或重定向SMT

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