CVE-2023-51310 identifies a vulnerability in PHPJabbers Car Park Booking System version 3.0, specifically in the 'Forgot Password' and 'Email Settings' functionalities. The root cause is the absence of rate limiting controls, which allows an authenticated attacker to repeatedly trigger email sending operations. This can result in the generation of a large volume of emails for a legitimate user account, potentially overwhelming the email infrastructure and causing a Denial of Service (DoS) condition. The vulnerability is categorized under CWE-770 (Allocation of Resources Without Limits or Throttling), indicating that the system fails to restrict resource consumption appropriately. The CVSS v3.1 base score is 4.3 (medium), with vector AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L, meaning the attack can be performed remotely over the network with low complexity, requires privileges (authenticated user), no user interaction, and impacts availability only. No patches or known exploits are currently documented, but the risk lies in potential service disruption through resource exhaustion. The vulnerability does not compromise data confidentiality or integrity but can degrade service availability, affecting user experience and operational continuity.

For European organizations using PHPJabbers Car Park Booking System v3.0, this vulnerability poses a risk of service disruption through email system overload. The excessive email generation can lead to denial of service, affecting the availability of email notifications critical for user account management and booking confirmations. This could degrade customer trust and operational efficiency, especially in sectors relying on timely communication such as transportation, parking management, and event venues. Additionally, the flood of emails could trigger spam filters or blacklisting of the organization's email domain, further impacting communication channels. While the vulnerability requires authenticated access, insider threats or compromised accounts could exploit it. The impact is primarily operational rather than data breach-related, but the resulting downtime or communication failure could have cascading effects on business processes and customer satisfaction.

To mitigate CVE-2023-51310, organizations should implement strict rate limiting on email-triggering functionalities within the PHPJabbers Car Park Booking System, particularly for 'Forgot Password' and 'Email Settings' features. This can be achieved by configuring application-level throttling to restrict the number of emails sent per user within a defined time window. Additionally, monitoring and alerting mechanisms should be established to detect unusual spikes in email activity. Employing CAPTCHA or multi-factor authentication on sensitive forms can reduce automated abuse. Organizations should also review user access controls to minimize the risk of compromised accounts being used for exploitation. If possible, updating to a patched version or applying vendor-provided fixes is recommended once available. Network-level email rate limiting and outbound email filtering can provide an additional layer of defense. Finally, educating users and administrators about this risk and encouraging prompt reporting of suspicious activity will enhance overall resilience.