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The vulnerability resides in the `ThreadPolicy::edit()` method within FreeScout versions 1.8.208 and below. This method is responsible for determining whether an authenticated user has permission to modify a thread message. The flaw lies in a broken access control mechanism where the policy logic fails to verify the user’s mailbox association or role before granting edit permissions. Instead of enforcing the configured mailbox permissions, the method improperly defaults to allowing any authenticated user to modify customer-created thread messages. An attacker with a low-privileged account (e.g., a user who should only have access to a single mailbox) can craft requests to edit threads belonging to any mailbox. This bypasses the intended role-based access control (RBAC) and mailbox isolation, enabling unauthorized modification of message content, which leads to evidence tampering, data integrity issues, and potential violations of data protection regulations like GDPR.
dailycve form:
Platform: FreeScout
Version: 1.8.208 and below
Vulnerability: Broken Access Control
Severity: Critical
date: March 19, 2026
Prediction: March 19, 2026
What Undercode Say:
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Check current FreeScout version
php artisan freescout:version
Audit for unauthorized thread modifications in logs
grep "ThreadPolicy::edit" storage/logs/laravel.log | grep -v "authorized"
Test for the vulnerability using cURL (requires authenticated session token)
curl -X PUT https://target.com/api/threads/{thread_id} \
-H "X-CSRF-TOKEN: {token}" \
-H "Cookie: laravel_session={session}" \
-d "content=Malicious+Modification"
Exploit:
- Authenticate as any user with minimal permissions (e.g., a user assigned to a single mailbox).
- Obtain the `thread_id` of a message from a mailbox the user does not have access to.
- Send a PUT/PATCH request to the thread edit endpoint (e.g.,
/threads/{thread_id}) with the modified content. - The `ThreadPolicy::edit()` method fails to restrict access, allowing the unauthorized modification to be saved.
Protection from this CVE:
- Upgrade to FreeScout version 1.8.209 or later immediately.
- If immediate upgrade is not possible, implement strict middleware to validate mailbox membership before any thread modification request.
- Audit current thread messages for unauthorized edits by comparing timestamps and user IDs with expected permissions.
Impact:
- Unauthorized modification of customer messages across all mailboxes.
- Complete bypass of mailbox permission model and role-based access controls.
- Evidence tampering leading to potential fraud and loss of data integrity.
- Severe compliance violations under GDPR and other data protection regulations due to unauthorized data alteration.
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Sources:
Reported By: nvd.nist.gov
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