CVE-2025-59413 is a medium-severity vulnerability affecting CubeCart version 6 prior to 6.5.11. CubeCart is an ecommerce platform widely used for online retail operations. The vulnerability is classified under CWE-862, which denotes a Missing Authorization flaw. Specifically, the issue exists in the newsletter subscription endpoint of the software. An attacker can exploit a logic flaw by manipulating the 'force_unsubscribe' parameter in a POST request. By setting this parameter to '1', the attacker can forcibly unsubscribe any valid subscriber's email address without their consent or any authentication. This results in unauthorized modification of subscription data, impacting the integrity and availability of the newsletter subscription service. The vulnerability does not affect confidentiality directly but can disrupt communication channels between the ecommerce store and its customers. The flaw requires no privileges or user interaction to exploit, and the attack vector is network-based (remote). The vulnerability has been patched in CubeCart version 6.5.11, and users are advised to upgrade to this or later versions to remediate the issue. There are no known exploits in the wild at the time of publication.

For European organizations using CubeCart as their ecommerce platform, this vulnerability can lead to disruption in customer communications by unauthorized removal of subscribers from newsletters. This can degrade customer engagement, marketing effectiveness, and potentially harm brand reputation. While it does not directly lead to data breaches or financial theft, the integrity and availability of marketing channels are compromised. In sectors where customer communication is critical, such as retail, hospitality, and services, this could indirectly affect revenue and customer trust. Additionally, repeated or large-scale exploitation could be used as a denial-of-service vector against the newsletter system. Since the vulnerability requires no authentication and can be exploited remotely, attackers could automate mass unsubscribes, causing significant operational disruption. European organizations with strict data protection regulations (e.g., GDPR) must also consider the implications of unauthorized data manipulation, even if personal data confidentiality is not breached.

The primary mitigation is to upgrade CubeCart installations to version 6.5.11 or later, where the vulnerability has been patched. Organizations should implement strict input validation and authorization checks on all endpoints, especially those modifying user subscription data. Specifically, the newsletter subscription endpoint must verify that any unsubscribe requests originate from authorized users or verified sources. Implementing multi-factor verification for subscription changes or confirmation emails can help prevent unauthorized modifications. Monitoring and alerting on unusual unsubscribe patterns can detect exploitation attempts early. Additionally, applying web application firewalls (WAFs) with rules to detect and block suspicious POST requests targeting the 'force_unsubscribe' parameter can provide a temporary protective layer. Regular security audits and penetration testing focused on authorization logic flaws should be conducted to identify similar issues proactively.