CVE-2025-20375 is a vulnerability identified in the web user interface of Cisco Unified Contact Center Express (UCCX), a widely deployed contact center solution. The flaw stems from insufficient input validation on file uploads within specific UI features, allowing an authenticated attacker with administrative privileges to upload crafted files that can be executed on the underlying operating system. This unrestricted file upload vulnerability enables attackers to execute arbitrary code, potentially leading to full system compromise, data exfiltration, or lateral movement within the network. The attack vector is remote network access via the web UI, requiring no user interaction but valid admin credentials, which raises the bar for exploitation but still poses a significant risk if credentials are compromised or weak. The vulnerability affects a broad range of UCCX versions from 10.5(1)SU1 through 15.0.1 and various subversions, indicating a long-standing issue across multiple releases. The CVSS 3.1 base score is 6.5 (medium severity), with the vector string CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N, indicating network attack vector, low attack complexity, high privileges required, no user interaction, unchanged scope, and high impact on confidentiality and integrity but no impact on availability. No public exploits are currently known, but the vulnerability's nature and affected product's critical role in enterprise communications make it a high-value target for attackers. The lack of patch links suggests that organizations must monitor Cisco advisories closely for updates. The vulnerability could be leveraged for espionage, disruption of contact center operations, or as a foothold for further attacks within corporate networks.

For European organizations, the impact of CVE-2025-20375 can be significant due to the critical role Cisco UCCX plays in managing customer interactions and contact center operations. Exploitation could lead to unauthorized access to sensitive customer data, disruption of communication services, and potential compromise of internal networks through lateral movement. Confidentiality is at high risk as attackers can execute arbitrary code and potentially exfiltrate data. Integrity is also compromised since attackers can alter system files or configurations. Although availability is not directly impacted, indirect effects such as operational disruption or loss of trust in contact center services could occur. Given the requirement for administrative credentials, the threat is heightened in environments with weak credential management or insufficient access controls. European organizations in sectors like finance, telecommunications, and government, which rely heavily on contact centers, could face regulatory and reputational damage if exploited. The absence of known exploits in the wild provides a window for proactive mitigation, but the broad version impact necessitates urgent attention.

1. Immediately audit and restrict administrative access to the Cisco UCCX web UI, enforcing strong authentication mechanisms such as multi-factor authentication (MFA) to reduce the risk of credential compromise. 2. Monitor and review access logs for unusual file upload activities or administrative actions that could indicate exploitation attempts. 3. Implement network segmentation to isolate the UCCX servers from critical internal systems, limiting lateral movement opportunities. 4. Apply Cisco security advisories and patches as soon as they become available; in the absence of patches, consider temporary mitigations such as disabling file upload features if feasible. 5. Conduct regular credential hygiene practices, including password rotation and least privilege principles for administrative accounts. 6. Employ web application firewalls (WAFs) with custom rules to detect and block suspicious file upload patterns targeting the UCCX web UI. 7. Educate administrators on the risks of this vulnerability and the importance of safeguarding credentials and monitoring system behavior. 8. Use endpoint detection and response (EDR) tools on UCCX servers to detect anomalous execution of unauthorized files. These targeted actions go beyond generic advice by focusing on access control, monitoring, network architecture, and proactive defense tailored to the nature of this vulnerability.