CVE-2026-4590 is a security vulnerability classified as a cross-site request forgery (CSRF) affecting kalcaddle kodbox version 1.64. The vulnerability exists in the loginSubmit API function located in the oauth plugin's bind controller (index.class.php). It involves manipulation of the 'third' argument, which can be exploited to trick authenticated users into submitting unauthorized requests to the application. CSRF attacks exploit the trust that a web application places in the user's browser, allowing attackers to perform actions without the user's explicit consent. In this case, the vulnerability requires the attacker to craft a malicious request that an authenticated user must unknowingly execute, which is complicated by the high attack complexity and the need for user interaction. The vulnerability is remotely exploitable without requiring privileges or authentication but does not impact confidentiality or availability significantly. The vendor was notified but did not respond, and no official patches have been released. The public availability of an exploit increases the risk, although no active exploitation in the wild has been reported. The CVSS 4.0 score of 2.3 reflects the low severity due to the difficulty of exploitation and limited impact on system security.

The primary impact of CVE-2026-4590 is the potential for unauthorized actions to be performed on behalf of authenticated users, which could lead to unintended changes or operations within the kodbox application. While the vulnerability does not directly compromise confidentiality or availability, it undermines the integrity of user sessions and trust in the application. For organizations relying on kodbox 1.64 for file management or collaboration, this could result in unauthorized modifications or binding of accounts, potentially leading to further security issues if combined with other vulnerabilities. The difficulty of exploitation and requirement for user interaction limit the scope and scale of potential attacks, reducing the overall risk. However, the public release of an exploit increases the likelihood of opportunistic attacks, especially against less security-aware users or poorly configured environments.

To mitigate CVE-2026-4590, organizations should implement strict anti-CSRF protections such as synchronizer tokens or double-submit cookies in the kodbox application, particularly for the loginSubmit API and related OAuth binding functions. Since no official patch is available, administrators should consider restricting access to the affected plugin or disabling the OAuth binding feature if not essential. Employing web application firewalls (WAFs) with rules to detect and block CSRF attempts can provide additional defense. User education about the risks of clicking unknown links while authenticated can reduce the likelihood of successful exploitation. Monitoring application logs for unusual binding requests or suspicious activity related to the 'third' argument may help detect attempted attacks. Finally, organizations should maintain regular backups and prepare incident response plans to address potential misuse stemming from this vulnerability.