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CVE-2026-40569 Detail

Description

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., `[email protected]`) 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.


Metrics

NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://github.com/freescout-help-desk/freescout/commit/f45b9105d43b0352c08fcca154e8ae6177c3d860 GitHub, Inc.
https://github.com/freescout-help-desk/freescout/releases/tag/1.8.213 GitHub, Inc.
https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-hmqm-33wp-858j CISA-ADP, GitHub, Inc.

Weakness Enumeration

CWE-ID CWE Name Source
CWE-284 Improper Access Control GitHub, Inc.  
CWE-915 Improperly Controlled Modification of Dynamically-Determined Object Attributes GitHub, Inc.  

Change History

2 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-40569
NVD Published Date:
04/21/2026
NVD Last Modified:
04/21/2026
Source:
GitHub, Inc.