CVE-2025-48481 in freescout
Summary
by MITRE • 05/30/2025
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 invite_hash, 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.
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Analysis
by VulDB Data Team • 05/30/2025
This vulnerability in FreeScout represents a critical access control flaw that undermines the platform's user authentication and account management systems. The issue stems from insufficient validation of invitation state during the account activation process, allowing unauthorized users to bypass normal account restrictions. The vulnerability specifically affects versions prior to 1.8.180 where the system fails to properly verify whether an invitation has been revoked, deleted, or blocked before permitting account activation. This creates a persistent security weakness that directly violates fundamental principles of secure authentication and access control mechanisms.
The technical exploitation occurs through manipulation of the invite_hash parameter within the invitation link, which serves as the primary authentication token for account activation. Attackers can leverage this weakness by obtaining an invitation link for an account that should be blocked or deleted, then use the same hash to activate the account regardless of its intended status. The vulnerability essentially allows for account takeover through unauthorized activation, bypassing the intended security controls that should prevent access to compromised or restricted accounts. This flaw operates at the application logic level, specifically within the account activation workflow where proper state validation is missing.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it enables attackers to potentially gain persistent access to shared mailboxes and help desk functionality. Once activated, compromised accounts can be used to view sensitive customer information, manipulate support tickets, and potentially escalate privileges within the system. The vulnerability affects the integrity of the entire user management system, as it allows attackers to circumvent account lifecycle management controls that should prevent access to deleted or blocked users. This creates a significant risk for organizations relying on FreeScout for customer support and shared mailbox management, particularly in environments where sensitive data is handled.
Organizations should immediately upgrade to FreeScout version 1.8.180 or later to remediate this vulnerability, as the patch addresses the core issue in the invitation validation logic. Additional mitigations include implementing proper monitoring of account activation events and establishing automated alerts for suspicious activation patterns. Security teams should also review existing user accounts for potential compromise and consider implementing additional authentication controls such as multi-factor authentication. The vulnerability aligns with CWE-639 which addresses authentication bypass through improper validation of user credentials or access tokens, and represents a clear violation of the principle of least privilege as outlined in the NIST Cybersecurity Framework. From an ATT&CK perspective, this vulnerability maps to T1078 legitimate credentials and T1531 account access removal, as it enables unauthorized access through compromised invitation mechanisms while potentially bypassing normal account management controls.