CVE-2026-53596

FreeScout is a free help desk and shared inbox built with the Laravel framework. Prior to version 1.8.214, the Change Customer modal correctly hides out-of-scope customers, but the backend conversation_change_customer action accepts any supplied customer_email.

FreeScout prior to version 1.8.217 had a vulnerability in the Helper::sanitizeRemoteUrl() function that improperly validated URLs after HTTP redirects. An attacker could exploit this vulnerability to redirect traffic to internal HTTP services that would normally be blocked.

FreeScout prior to version 1.8.217 allows users with updateAutoReply permission to store an XSS payload in the auto-reply message. The payload is rendered unescaped in the auto-reply email sent to customers.

In FreeScout before version 1.8.224, the public endpoint `POST /user-setup/{hash}/{invite_sent_at}` allows an attacker to take over a user account without authentication. The vulnerability is due to trailing space equality in MySQL/MariaDB VARCHAR and improper decryption of the `invite_sent_at` parameter.

FreeScout prior to version 1.8.217 has a vulnerability in the /user-setup/{hash} endpoint that accepts a 60-character random invite_hash to set a new user's password. The lack of expiration check allows for unauthorized account takeover long after the invite was issued.

FreeScout prior to version 1.8.224 has a vulnerability in the App Logs feature that allows an authenticated attacker to download arbitrary server-local files readable by the PHP process via manipulation of the dl parameter.

FreeScout before version 1.8.224 has an incomplete denylist of dangerous file extensions, missing the .pht extension. An authenticated agent can upload a .pht web shell, leading to remote code execution on the web server.

A Prototype Pollution vulnerability in the getQueryParam function in /public/js/main.js in FreeScout. The fix in version 1.8.139 is incomplete, allowing attacks via nested URL keys. Fixed in version 1.8.223.

Vulnerability in FreeScout before version 1.8.223. An unauthenticated attacker can inject a message into any existing support conversation by sending an email with a crafted In-Reply-To header. The message appears as a customer reply, and the conversation is automatically reopened.

Vulnerability in FreeScout (versions prior to 1.8.221) in the attachment download mechanism. An unauthenticated attacker can download any attachment created by an older version because token authentication is skipped for attachments with legacy token type.