CVE-2025-64663 is a critical vulnerability classified under CWE-918 (Server-Side Request Forgery) found in Microsoft Azure Cognitive Service for Language, specifically impacting the Custom Question Answering feature. SSRF vulnerabilities allow attackers to induce the server to make HTTP requests to arbitrary domains, including internal or protected network resources that are otherwise inaccessible externally. In this case, the vulnerability enables an attacker with limited privileges (PR:L) to escalate their privileges by exploiting the SSRF flaw, potentially gaining unauthorized access to sensitive data or internal services. The vulnerability does not require user interaction (UI:N) and can be exploited remotely (AV:N), which increases its risk profile. The CVSS vector indicates a complete impact on confidentiality, integrity, and availability (C:H/I:H/A:H), and the scope is changed (S:C), meaning the vulnerability affects resources beyond the initially vulnerable component. Although no public exploits have been reported yet, the high CVSS score (9.9) reflects the critical nature of this flaw. The lack of currently available patches necessitates immediate risk mitigation through network segmentation, strict egress filtering, and monitoring outbound traffic from the Azure Cognitive Service environment. This vulnerability is particularly concerning because Azure Cognitive Services are widely used for AI-driven language processing tasks, and exploitation could lead to data exfiltration, service disruption, or lateral movement within cloud environments.

For European organizations, the impact of CVE-2025-64663 can be substantial. Many enterprises and public sector entities in Europe rely on Microsoft Azure Cognitive Services for language processing, including natural language understanding and custom question answering, to enhance customer service, automate workflows, and analyze data. Exploitation of this SSRF vulnerability could allow attackers to access internal services, exfiltrate sensitive data, or disrupt critical AI-driven applications. This could lead to significant operational downtime, loss of intellectual property, and regulatory compliance violations under GDPR due to unauthorized data access. Additionally, the elevation of privilege aspect means attackers could escalate their access within the cloud environment, potentially compromising other linked services or infrastructure. The critical nature of the vulnerability and the widespread adoption of Azure services in Europe heighten the risk to sectors such as finance, healthcare, government, and telecommunications, where data sensitivity and service availability are paramount.

1. Apply official patches from Microsoft immediately once they become available to address CVE-2025-64663. 2. Until patches are released, implement strict network egress filtering to restrict outbound HTTP requests from Azure Cognitive Service instances, limiting them to only trusted endpoints. 3. Use Azure Private Link or service endpoints to isolate Azure Cognitive Services from public internet access, reducing exposure to SSRF exploitation. 4. Monitor logs and network traffic for unusual or unexpected outbound requests originating from the Custom Question Answering service. 5. Enforce the principle of least privilege by limiting user and service permissions to the minimum necessary to operate. 6. Conduct regular security assessments and penetration testing focused on cloud AI services to detect potential SSRF or related vulnerabilities. 7. Educate development and operations teams about SSRF risks and secure coding practices when integrating with Azure Cognitive Services. 8. Consider implementing Web Application Firewalls (WAF) or Azure-native security controls that can detect and block SSRF attack patterns.