CVE-2025-20375 is a vulnerability identified in the web user interface of Cisco Unified Contact Center Express (UCCX) that permits an authenticated remote attacker with administrative credentials to upload and execute arbitrary files on the affected system. The root cause is insufficient input validation in specific UI features that handle file uploads. An attacker can craft a malicious file and upload it through the web UI, bypassing restrictions on file types, which leads to arbitrary code execution on the underlying operating system. This can result in a complete system compromise, allowing the attacker to access sensitive data, alter system configurations, or disrupt services. The vulnerability affects a broad range of UCCX versions from 10.5(1) through 15.0.1, including many service updates and extended support releases, indicating a wide attack surface. The CVSS v3.1 base score is 6.5 (medium severity), reflecting the requirement for high privileges (administrative access) but ease of network exploitation without user interaction. No public exploits or active exploitation have been reported to date. Cisco has not yet published patches, so organizations must rely on compensating controls until updates are available.

For European organizations, the impact of this vulnerability can be significant, especially for enterprises and service providers relying on Cisco UCCX for customer contact management and telephony services. Successful exploitation could lead to unauthorized access to sensitive customer data, disruption of contact center operations, and potential lateral movement within corporate networks. This could affect confidentiality and integrity of data and potentially cause reputational damage and regulatory non-compliance under GDPR. Given the critical role of contact centers in customer service and business continuity, exploitation could also impact availability indirectly through operational disruptions. The requirement for administrative credentials limits the attack vector to insider threats or compromised admin accounts, but the risk remains substantial due to the privileged access gained upon exploitation.

1. Apply Cisco security patches immediately once they become available for all affected UCCX versions. 2. Restrict administrative access to the UCCX web UI using network segmentation, VPNs, and IP whitelisting to minimize exposure. 3. Enforce strong multi-factor authentication (MFA) for all administrative accounts to reduce the risk of credential compromise. 4. Monitor and audit all file upload activities and administrative actions within the UCCX environment to detect suspicious behavior early. 5. Implement strict input validation and file type restrictions at the application layer if possible through custom configurations or web application firewalls. 6. Regularly review and rotate administrative credentials and limit the number of users with high privileges. 7. Conduct security awareness training for administrators to recognize phishing and social engineering attempts that could lead to credential theft. 8. Maintain up-to-date backups and incident response plans to quickly recover from potential compromises.