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critical·Product Based Network Vulnerabilities·Updated Sep 10, 2026

CVE-2026-53595 Scanner

CVE-2026-53595 Scanner - Authorization Bypass vulnerability in FreeScout

Est. Time~10 seconds
Scan TypeGroup Scan
Targetsdomain, subdomain, ipv4
CostFree
3
Times Used
continuous scan runs
6.1k
Continuously Checked
assets under CS
0
Vulnerabilities Found
confirmed findings
References
CVECVE-2026-53595
9.4
CVSScritical
Exploitable remotely over the internet · no authentication required.

FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. Prior to version 1.8.224, the public endpoint `POST /user-setup/{hash}/{invite_sent_at}` (`OpenController@userSetupSave`) selects the target account solely by its `invite_hash` column, then overwrites that account's email and password and logs in as it. No authentication, cookie, or prior session is required. After a user activates, FreeScout sets `invite_hash` to the empty string. On MySQL and MariaDB, `VARCHAR` equality ignores trailing spaces, so a single URL-encoded space (`%20`) matches the stored empty string and selects the lowest-id activated user. The expiry guard decrypts `invite_sent_at` with the target's password hash, but `Helper::decrypt` returns its raw input unchanged when decryption fails. A plaintext numeric value such as `9999999999` therefore passes the time-to-live check without any secret. The result is that an anonymous attacker sets the email and password of the lowest-id activated FreeScout account (a support agent, or an administrator if one was added by invitation) and authenticates as that account. Version 1.8.224 contains a fix.

Attack Vector
Network
Privileges Req.
None
User Interaction
None
Affected
freescoutby freescout-help-desk
< 1.8.224
Updated Sep 10, 2026View on NVD →
Detail

FreeScout is an open-source help desk and shared inbox software that is frequently used by small to medium enterprises to manage customer inquiries and support requests. Its user base includes customer support teams who benefit from its collaborative features for handling service requests. The platform allows for integration with various email services, enabling streamlined communication and management of tasks. Freelancers and small companies utilize FreeScout for its cost-effectiveness and simplicity in setup and maintenance. It is often selected for its strong community support and the adaptability it offers through modular plugins and customization. Security is a significant concern for the users who rely on FreeScout for their daily operations, particularly regarding data integrity and user access management.

The Authorization Bypass vulnerability identified in FreeScout prior to version 1.8.224 is a critical flaw that allows unauthorized access to the application. This vulnerability is due to the mishandling of the invite_hash during the decryption process at the user setup endpoint. An attacker, without needing any authentication, can exploit this vulnerability to bypass security measures by resetting the credentials of the lowest-id activated user. This security gap provides potential attackers with the ability to gain unauthorized access, including administrator privileges. The bypass can lead to severe implications, primarily due to inadequate input validation and security measures in the invitation handling process.

In FreeScout, the endpoint responsible for user setup does not adequately validate the invite_hash, leading to an Authentication Bypass. The technical flaw lies in the application's failure to correctly handle decryption, which results in allowing unauthorized entities to interact with protected resources. Specifically, the vulnerable endpoint can be tricked into accepting incorrect data, thereby offering a pathway for intruders to reset and control user credentials. The endpoint fails to authenticate these requests properly, enabling attackers to gain access without legitimate credentials. The lack of proper input handling in this area makes the bypass particularly effective for automated attacks using forged invite_hash values. As such, the compromised parameter is a critical access point that should have stricter security checks.

If exploited, this vulnerability allows attackers to hijack user accounts and potentially escalate privileges within the FreeScout application. Malicious users can manipulate the application to alter user credentials, which can result in unauthorized access to sensitive data and system administration capabilities. This can lead to a complete takeover of affected systems, affecting not only the confidentiality of customer communications but also the integrity and availability of the service. Recovery from such an exploit can be costly and time-consuming, demanding thorough security audits and potential data recovery efforts. Organizations using vulnerable versions of FreeScout may face significant operational disruptions and reputational damage.

REFERENCES

Solution Advice
  • Upgrade FreeScout to version 1.8.224 or later to patch the vulnerability.
  • Review and restrict access to the invite_hash functionality to ensure proper authorization checks are enforced.
  • Implement additional logging and monitoring to detect unauthorized access attempts swiftly.
  • Conduct a security audit on current permission configurations to identify other possible vulnerabilities.
  • Educate staff about security best practices to mitigate the human element of such exploits.

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CVE-2026-53595 Scanner - Authorization Bypass vulnerability in FreeScout | S4E