FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. A patch bypass vulnerability for CVE-2026-27636 in FreeScout 1.8.206 and earlier allows any authenticated user with file upload permissions to achieve Remote Code Execution (RCE) on the server by uploading a malicious .htaccess file using a zero-width space character prefix to bypass the security check. The vulnerability exists in the sanitizeUploadedFileName() function in app/Http/Helper.php. The function contains a Time-of-Check to Time-of-Use (TOCTOU) flaw where the dot-prefix check occurs before sanitization removes invisible characters. This vulnerability is fixed in 1.8.207.

FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.179, the application does not check or performs insufficient checking of files uploaded to the application. This allows files to be uploaded with the phtml and phar extensions, which can lead to remote code execution if the Apache web server is used. This issue has been patched in version 1.8.179.

FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.180, an attacker with an unactivated email invitation containing invitehash, can exploit this vulnerability to self-activate their account, despite it being blocked or deleted, by leveraging the invitation link from the email to gain initial access to the account. This issue has been patched in version 1.8.180.

FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. Prior to version 1.8.206, FreeScout's TokenAuth middleware uses a predictable authentication token computed as MD5(userid + createdat + APPKEY). This token is static (never expires/rotates), and if an attacker obtains the APPKEY — a well-documented and common exposure vector in Laravel applications — they can compute a valid token for any user, including the administrator, achieving full account takeover without any password. This vulnerability can be exploited on its own or in combination with CVE-2026-27636. Version 1.8.206 fixes both vulnerabilities.

FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. Versions 1.8.208 and below are vulnerable to Stored Cross-Site Scripting (XSS) through FreeScout's email notification templates. Incoming email bodies are stored in the database without sanitization and rendered unescaped in outgoing email notifications using Blade's raw output syntax {!! $thread->body !!}. An unauthenticated attacker can exploit this vulnerability by simply sending an email, and when opened by any subscribed agent or admin as part of their normal workflow, enabling universal HTML injection (phishing, tracking) and, in vulnerable email clients, JavaScript execution (session hijacking, credential theft, account takeover) affecting all recipients simultaneously. This issue has been fixed in version 1.8.209.

FreeScout is a self-hosted help desk and shared mailbox. Versions prior to 1.8.128 are vulnerable to OS Command Injection in the /public/tools.php source file. The value of the phppath parameter is being executed as an OS command by the shellexec function, without validating it. This allows an adversary to execute malicious OS commands on the server. A practical demonstration of the successful command injection attack extracted the /etc/passwd file of the server. This represented the complete compromise of the server hosting the FreeScout application. This attack requires an attacker to know the AppKey of the application. This limitation makes the Attack Complexity to be High. If an attacker gets hold of the AppKey, the attacker can compromise the Complete server on which the application is deployed. Version 1.8.128 contains a patch for this issue.

The End-User Portal module before 1.0.65 for FreeScout sometimes allows an attacker to authenticate as an arbitrary user because a session token can be sent to the /auth endpoint. NOTE: this module is not part of freescout-helpdesk/freescout on GitHub.

FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.215, FreeScout's module installation feature extracts ZIP archives without validating file paths, allowing an authenticated admin to write files arbitrarily on the server filesystem via a specially crafted ZIP. Version 1.8.215 fixes the vulnerability.

FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. Prior to version 1.8.217, the /user-setup/{hash} endpoint accepts a 60-character random invitehash to set a new user's password. The endpoint performs no expiration check — the hash remains valid indefinitely until consumed. Combined with realistic hash-leakage scenarios (forwarded invite emails, HTTP referrer to external CDNs on the setup page, server-side log exposure, abandoned invite emails in shared inboxes), this enables unauthenticated permanent account takeover months or years after invite issuance. If the leaked invite was sent to an admin, the takeover yields admin access. This issue has been patched in version 1.8.217.

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 autobcc, outserver, outpassword, signature, autoreplyenabled, and autoreplymessage. 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., autobcc=attacker@evil.com) to a legitimate connection settings save request. Because the autobcc 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.

FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.213, an unauthenticated attacker can access diagnostic and system tools that should be restricted to administrators. The /system/cron endpoint relies on a static MD5 hash derived from the APPKEY, which is exposed in the response and logs. Accessing these endpoints reveals sensitive server information (Full Path Disclosure), process IDs, and allows for Resource Exhaustion (DoS) by triggering heavy background tasks repeatedly without any rate limiting. The cron hash is generated using md5(APPKEY . 'webcronhash'). Since this hash is often transmitted via GET requests, it is susceptible to exposure in server logs, browser history, and proxy logs. Furthermore, the lack of rate limiting on these endpoints allows for automated resource exhaustion (DoS) and brute-force attempts. Version 1.8.213 fixes the issue.

FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.180, when adding and editing user records using the fill() method, there is no check for the absence of the password field in the data coming from the user, which leads to a mass-assignment vulnerability. As a result, a user with the right to edit other users of the system can change their password, and then log in to the system using the set password. This issue has been patched in version 1.8.180.

FreeScout is a lightweight free open source help desk and shared inbox built with PHP (Laravel framework). In versions 1.8.185 and below, there is a critical deserialization vulnerability in the /conversation/ajax endpoint that allows authenticated users with knowledge of the APPKEY to achieve remote code execution. The vulnerability occurs when the application processes the attachmentsall and attachments POST parameters through the insecure Helper::decrypt() function, which performs unsafe deserialization of user-controlled data without proper validation. This flaw enables attackers to create arbitrary objects and manipulate their properties, leading to complete compromise of the web application. This is fixed in version 1.8.186.

FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. Versions 1.8.185 and earlier contain a deserialization of untrusted data vulnerability that allows authenticated attackers with knowledge of the application's APPKEY to achieve remote code execution. The vulnerability is exploited via endpoint, e.g.: /help/{mailboxid}/auth/{customerid}/{hash}/{timestamp} where the customerid and timestamp parameters are processed through the decrypt function in app/Helper.php without proper validation. The code decrypts using Laravel's built-in encryption functions, which subsequently deserialize the decrypted payload without sanitization, allowing attackers to craft malicious serialized PHP objects using classes to trigger arbitrary command execution. This is fixed in version 1.8.186.

FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. Prior to version 1.8.206, FreeScout's file upload restriction list in app/Misc/Helper.php does not include .htaccess or .user.ini files. On Apache servers with AllowOverride All (a common configuration), an authenticated user can upload a .htaccess file to redefine how files are processed, enabling Remote Code Execution. This vulnerability can be exploited on its own or in combination with CVE-2026-27637. Version 1.8.206 fixes both vulnerabilities.

FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.213, attachment download tokens are generated using a weak and predictable formula: md5(APPKEY + attachmentid + size). Since attachmentid is sequential and size can be brute-forced in a small range, an unauthenticated attacker can forge valid tokens and download any private attachment without credentials. Version 1.8.213 fixes the issue.

FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.178, FreeScout is vulnerable to code injection due to insufficient validation of user input in the phppath parameter. The backticks characters are not removed, as well as tabulation is not removed. When checking user input, the fileexists function is also called to check for the presence of such a file (folder) in the file system. A user with the administrator role can create a translation for the language, which will create a folder in the file system. Further in tools.php, the user can specify the path to this folder as phppath, which will lead to the execution of code in backticks. This issue has been patched in version 1.8.178.

FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.178, FreeScout is vulnerable to deserialization of untrusted data due to insufficient validation. Through the set function, a string with a serialized object can be passed, and when getting an option through the get method, deserialization will occur, which will allow arbitrary code execution This issue has been patched in version 1.8.178.

FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.180, the laravel-translation-manager package does not correctly validate user input, enabling the deletion of any directory, given sufficient access rights. This issue has been patched in version 1.8.180.

FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. In versions 1.8.208 and below, bypasses of the attachment view logic and SVG sanitizer make it possible to upload and render an SVG that runs malicious JavaScript. An extension of .png with content type of image/svg+xml is allowed, and a fallback mechanism on invalid XML leads to unsafe sanitization. The application restricts which uploaded files are rendered inline: only files considered "safe" are displayed in the browser; others are served with Content-Disposition: attachment. This decision is based on two checks: the file extension (e.g. .png is allowed, while .svg may not be) and the declared Content-Type (e.g. image/ is allowed). By using a filename with an allowed extension (e.g. xss.png) and a Content-Type of image/svg+xml, an attacker can satisfy both checks and cause the server to treat the upload as a safe image and render it inline, even though the body is SVG and can contain scripted behavior. Any authenticated user can set up a specific URL, and whenever another user or administrator visits it, XSS can perform any action on their behalf. This issue has been fixed in version 1.8.209.

FreeScout is a free self-hosted help desk and shared mailbox. Versions prior to 1.8.213 have a stored cross-site scripting (XSS) vulnerability in the mailbox signature feature. The sanitization function Helper::stripDangerousTags() (app/Misc/Helper.php:568) uses an incomplete blocklist of only four HTML tags (script, form, iframe, object) and does not remove event handler attributes. When a mailbox signature is saved via MailboxesController::updateSave() (app/Http/Controllers/MailboxesController.php:267), HTML elements such as <img>, <svg>, and <details> with event handler attributes like onerror and onload pass through sanitization unchanged and are stored in the database. The signature is then rendered as raw HTML via the Blade {!! !!} tag in editorbottomtoolbar.blade.php:6 and re-inserted into the visible DOM by jQuery .html() at main.js:1789-1790, triggering the injected event handlers. Any authenticated user with the ACCESSPERMSIGNATURE (sig) permission on a mailbox -- a delegatable, non-admin permission -- can inject arbitrary HTML and JavaScript into the mailbox signature. The payload fires automatically, with no victim interaction, whenever any agent or administrator opens any conversation in the affected mailbox. This enables session hijacking (under CSP bypass conditions such as IE11 or module-weakened CSP), phishing overlays that work in all browsers regardless of CSP, and chaining to admin-level actions including email exfiltration via mass assignment and self-propagating worm behavior across all mailboxes. Version 1.8.213 fixes the issue.

FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.179, there is no check to ensure that the user is disabling notifications for the mailbox to which they already have access. Moreover, the code explicitly implements functionality that if the user does not have access to the mailbox, then after disabling (enabling) notifications for this mailbox, the user will gain access to it. This issue has been patched in version 1.8.179.

FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.180, the application incorrectly checks user access rights for conversations. Users with showonlyassignedconversations enabled can assign themselves to an arbitrary conversation from the mailbox to which they have access, thereby bypassing the restriction on viewing conversations. This issue has been patched in version 1.8.180.

FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.180, the System does not provide a check on which "clients" of the System an authorized user can view and edit, and which ones they cannot. As a result, an authorized user who does not have access to any of the existing mailboxes, as well as to any of the existing conversations, has the ability to view and edit the System's clients. The limitation of client visibility can be implemented by the limitusercustomervisibility setting, however, in the specified scenarios, there is no check for the presence of this setting. This issue has been patched in version 1.8.180.

FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.180, the application's logic requires the user to perform a correct sequence of actions to implement a functional capability, but the application allows access to the functional capability without correctly completing one or more actions in the sequence. The leaves the attributes of Mailbox object able to be changed by the fill method. This issue has been patched in version 1.8.180.

FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. In versions 1.8.208 and below, the ThreadPolicy::edit() method contains a broken access control vulnerability that allows any authenticated user (regardless of role or mailbox access) to read and modify all customer-created thread messages across all mailboxes. This flaw enables silent modification of customer messages (evidence tampering), bypasses the entire mailbox permission model, and constitutes a GDPR/compliance violation. The issue has been fixed in version 1.8.209.

FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.213, FreeScout's Helper::stripDangerousTags() removes <script>, <form>, <iframe>, <object> but does NOT strip <style> tags. The mailbox signature field is saved via POST /mailbox/settings/{id} and later rendered unescaped via {!! $conversation->getSignatureProcessed([], true) !!} in conversation views. CSP allows style-src 'self' 'unsafe-inline', so injected inline styles execute freely. An attacker with access to mailbox settings (admin or agent with mailbox permission) can inject CSS attribute selectors to exfiltrate the CSRF token of any agent/admin who views a conversation in that mailbox. With the CSRF token, the attacker can perform any state-changing action as the victim (create admin accounts, change email/password, etc.) — privilege escalation from agent to admin. This is the result of an incomplete fix of GHSA-jqjf-f566-485j. That advisory reported XSS via mailbox signature. The fix applied Helper::stripDangerousTags() to the signature before saving. However, stripDangerousTags() only removes script, form, iframe, and object tags — it does NOT strip <style> tags, leaving CSS injection possible. Version 1.8.213 contains an updated fix.

FreeScout is a self-hosted help desk and shared mailbox. A Stored Cross-Site Scripting (XSS) vulnerability has been identified within the Signature Input Field of the FreeScout Application prior to version 1.8.128. Stored XSS occurs when user input is not properly sanitized and is stored on the server, allowing an attacker to inject malicious scripts that will be executed when other users access the affected page. In this case, the Support Agent User can inject malicious scripts into their signature, which will then be executed when viewed by the Administrator.

The application protects users against XSS attacks by enforcing a CSP policy, the CSP Policy is: script-src 'self' 'nonce-abcd' . The CSP policy only allows the inclusion of JS files that are present on the application server and doesn't allow any inline script or script other than nonce-abcd. The CSP policy was bypassed by uploading a JS file to the server by a POST request to /conversation/upload endpoint. After this, a working XSS payload was crafted by including the uploaded JS file link as the src of the script. This bypassed the CSP policy and XSS attacks became possible.

The impact of this vulnerability is severe as it allows an attacker to compromise the FreeScout Application. By exploiting this vulnerability, the attacker can perform various malicious actions such as forcing the Administrator to execute actions without their knowledge or consent. For instance, the attacker can force the Administrator to add a new administrator controlled by the attacker, thereby giving the attacker full control over the application. Alternatively, the attacker can elevate the privileges of a low-privileged user to Administrator, further compromising the security of the application. Attackers can steal sensitive information such as login credentials, session tokens, personal identifiable information (PII), and financial data. The vulnerability can also lead to defacement of the Application.

Version 1.8.128 contains a patch for this issue.

FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. Prior to version 1.8.217, Helper::sanitizeRemoteUrl() in app/Misc/Helper.php follows HTTP redirects via curlGetLastRedirectedUrl() but then re-validates the original URL instead of the final redirect destination. An attacker who can supply any URL that passes the initial host check can redirect FreeScout to internal HTTP services (cloud metadata, internal APIs, RFC1918 ranges) that would normally be blocked. This issue has been patched in version 1.8.217.

FreeScout is a free, self-hosted help desk and shared mailbox. A stored HTML Injection vulnerability has been identified in the Email Receival Module of the Freescout Application. The vulnerability allows attackers to inject malicious HTML content into emails sent to the application's mailbox. This vulnerability arises from improper handling of HTML content within incoming emails, allowing attackers to embed malicious HTML code in the context of the application's domain. Unauthenticated attackers can exploit this vulnerability to inject malicious HTML content into emails. This could lead to various attacks such as form hijacking, application defacement, or data exfiltration via CSS injection. Although unauthenticated attackers are limited to HTML injection, the consequences can still be severe. Version 1.8.139 implements strict input validation and sanitization mechanisms to ensure that any HTML content received via emails is properly sanitized to prevent malicious HTML injections.