CVE-2025-48477: FreeScout Authentication Bypass Vulnerability

CVE-2025-48477 Overview

CVE-2025-48477 is a business logic flaw in FreeScout, a free self-hosted help desk and shared mailbox application. The vulnerability exists in versions prior to 1.8.180. The application enforces a sequence of actions to complete a functional capability, but allows access to that capability without correctly completing every step. As a result, attributes of the Mailbox object can be modified through the fill method by authenticated users. The issue is categorized under CWE-841: Improper Enforcement of Behavioral Workflow. FreeScout maintainers patched the issue in version 1.8.180.

Critical Impact
Authenticated low-privilege users can modify protected attributes of Mailbox objects, leading to confidentiality impact across the help desk application.

Affected Products

FreeScout versions prior to 1.8.180
Self-hosted FreeScout help desk deployments
Shared mailbox configurations managed by FreeScout

Discovery Timeline

2025-05-30 - CVE-2025-48477 published to NVD
2025-06-04 - Last updated in NVD database

Technical Details for CVE-2025-48477

Vulnerability Analysis

The vulnerability is a workflow bypass that exposes mass-assignment behavior on the Mailbox model. FreeScout requires users to complete a sequence of actions before reaching a specific mailbox configuration capability. The application fails to enforce that sequence, allowing users to invoke the capability directly. Once invoked, the underlying Laravel fill method writes user-controlled input to attributes of the Mailbox object. Because the model does not adequately restrict which attributes are fillable in this context, attacker-supplied parameters overwrite values that should be protected by the workflow.

The attack requires network access and a low-privileged authenticated session. No user interaction is required. The primary impact is to confidentiality of mailbox data, while integrity impact is limited and availability is not affected.

Root Cause

The root cause is improper enforcement of behavioral workflow [CWE-841] combined with overly permissive use of the fill method on the Mailbox Eloquent model. The application trusts that prior steps in the workflow validated the request context, but those steps can be skipped. Without server-side checks at the destination action, the model accepts arbitrary attribute assignments from request payloads.

Attack Vector

An authenticated attacker with low privileges sends a crafted HTTP request to the FreeScout endpoint that triggers the affected mailbox update path. By including additional attribute fields in the request body, the attacker influences fields that the intended workflow would have controlled. The vulnerability mechanism is documented in the FreeScout GitHub Security Advisory GHSA-2c82-qx7x-35h8. No public proof-of-concept exploit is available at the time of publication.

Detection Methods for CVE-2025-48477

Indicators of Compromise

Unexpected modifications to Mailbox attributes that were not changed through the standard administrative interface
HTTP POST or PUT requests to mailbox-related endpoints containing parameter names outside the documented workflow fields
Authenticated sessions from low-privilege accounts accessing mailbox configuration routes

Detection Strategies

Review FreeScout application logs for Mailbox update events correlated with non-administrative user roles
Compare database snapshots of the mailboxes table over time to identify silent attribute drift
Inspect web server access logs for direct POST requests to mailbox update endpoints that bypass the multi-step UI flow

Monitoring Recommendations

Enable verbose audit logging for FreeScout user activity on mailbox configuration
Forward FreeScout and reverse proxy logs to a centralized log platform for correlation and alerting
Establish a baseline of normal mailbox modification frequency and alert on deviations from low-privilege accounts

How to Mitigate CVE-2025-48477

Immediate Actions Required

Upgrade FreeScout to version 1.8.180 or later, where the workflow enforcement and fill behavior are corrected
Audit existing Mailbox records for unauthorized attribute changes after applying the patch
Review and tighten role assignments so only trusted users hold accounts capable of reaching authenticated endpoints

Patch Information

The maintainers released the fix in FreeScout 1.8.180. Upgrade instructions and the full advisory are available in the FreeScout GitHub Security Advisory GHSA-2c82-qx7x-35h8. Administrators should follow the standard FreeScout update procedure and verify the running version after deployment.

Workarounds

Restrict network access to the FreeScout web interface to trusted administrators until the patch is applied
Disable or remove low-privilege user accounts that do not require active access during the remediation window
Place FreeScout behind a reverse proxy that enforces request schema validation on mailbox update endpoints

bash

# Verify the installed FreeScout version after upgrade
cd /var/www/html/freescout
php artisan freescout:check-requirements
grep "'version'" config/app.php