CVE-2025-59816 is a high-severity SQL Injection vulnerability (CWE-89) affecting the Zenitel ICX500 product versions prior to 1.4.3.3. This vulnerability arises from improper neutralization of special elements used in SQL commands, allowing an attacker with at least low privileges (PR:L) to craft malicious input that is directly executed by the underlying database. The flaw enables unauthorized querying of the Billing Admin database, which contains sensitive information including user credentials. Notably, user passwords are stored in plaintext, significantly exacerbating the risk by allowing attackers to immediately leverage stolen credentials without needing to crack hashes. The vulnerability does not require user interaction (UI:N) and can be exploited remotely over the network (AV:N), making it highly accessible to attackers who have some level of authenticated access. The impact on confidentiality and integrity is high, as attackers can exfiltrate sensitive data and potentially manipulate billing information, although availability is not affected. No known exploits are currently reported in the wild, but the ease of exploitation combined with the sensitive nature of the data makes this a critical concern for affected organizations. The vulnerability was published on September 25, 2025, and is tracked under CVE-2025-59816 with a CVSS v3.1 base score of 8.1, reflecting its high severity. No patches or mitigation links are currently provided, indicating that organizations must urgently seek vendor updates or implement compensating controls to protect their environments.

For European organizations using Zenitel ICX500 systems, this vulnerability poses a significant risk to the confidentiality and integrity of billing and user credential data. The exposure of plaintext passwords could lead to credential theft and lateral movement within corporate networks, potentially compromising other systems if password reuse occurs. Billing data manipulation could result in financial losses or fraud. Given the network-exploitable nature of the flaw and the lack of required user interaction, attackers could automate exploitation, increasing the risk of widespread compromise. Organizations in sectors such as telecommunications, critical infrastructure, and enterprises relying on Zenitel communication solutions are particularly vulnerable. The breach of sensitive data could also lead to regulatory non-compliance under GDPR, resulting in legal and financial penalties. Furthermore, the reputational damage from such a breach could be severe, especially for companies providing communication services or handling sensitive customer data.

1. Immediate action should be taken to upgrade Zenitel ICX500 devices to version 1.4.3.3 or later once available from the vendor. 2. Until patches are released, restrict access to the Billing Admin interface to trusted internal networks only, using network segmentation and firewall rules. 3. Implement strong authentication and monitoring on accounts with access to the vulnerable interface to detect and prevent unauthorized access. 4. Conduct thorough audits of user credentials stored in the system and enforce password changes, especially since passwords are stored in plaintext. 5. Employ Web Application Firewalls (WAFs) with custom rules to detect and block SQL injection attempts targeting the ICX500 interfaces. 6. Monitor logs for unusual query patterns or access attempts indicative of exploitation attempts. 7. Engage with Zenitel support to obtain official patches or workarounds and confirm remediation timelines. 8. Educate administrators on the risks of SQL injection and the importance of input validation and secure coding practices for future deployments.