CVE-2025-61735 is a Server-Side Request Forgery (SSRF) vulnerability classified under CWE-918 affecting Apache Kylin versions from 4.0.0 up to 5.0.2. SSRF vulnerabilities occur when an attacker can abuse a server’s functionality to make HTTP requests to arbitrary domains or internal systems, potentially bypassing network access controls. In this case, the vulnerability allows unauthenticated remote attackers to craft requests that the Apache Kylin server will execute, which can lead to unauthorized information disclosure, manipulation of internal services, or denial of service. The vulnerability is exploitable over the network without requiring privileges or user interaction, increasing its risk profile. The CVSS v3.1 score of 7.3 indicates a high severity due to the combination of network attack vector, low complexity, no privileges required, and impacts on confidentiality, integrity, and availability. Apache Kylin is an open-source distributed analytics engine designed for big data, commonly used in enterprise environments for OLAP on Hadoop and cloud data platforms. The vulnerability stems from insufficient validation of URLs or endpoints that Kylin accesses internally, allowing attackers to redirect requests to internal or external systems. The recommended mitigation is upgrading to Apache Kylin version 5.0.3, which addresses the SSRF flaw. Until patched, securing admin access and restricting network access to Kylin instances can reduce exploitation risk. No public exploits or active attacks have been reported yet, but the vulnerability’s characteristics make it a significant risk for organizations relying on Apache Kylin for critical analytics workloads.

For European organizations, the impact of CVE-2025-61735 can be substantial, especially for those utilizing Apache Kylin in data analytics, finance, telecommunications, and government sectors. Exploitation could lead to unauthorized access to sensitive internal systems or data, undermining confidentiality. Attackers might pivot from the vulnerable Kylin server to internal networks, potentially compromising integrity by manipulating analytics results or injecting malicious data. Availability could also be affected if attackers leverage SSRF to trigger denial-of-service conditions on internal services or the Kylin server itself. Given the reliance on big data analytics for decision-making and regulatory compliance in Europe, such disruptions could have operational and reputational consequences. Additionally, GDPR and other data protection regulations impose strict requirements on data security; a breach facilitated by this vulnerability could result in regulatory penalties. The lack of required authentication lowers the barrier for attackers, increasing the likelihood of exploitation if systems are exposed to untrusted networks. Organizations with Kylin instances accessible from the internet or poorly segmented internal networks are at higher risk.

1. Upgrade Apache Kylin to version 5.0.3 immediately to apply the official patch addressing the SSRF vulnerability. 2. Restrict network access to Apache Kylin servers by implementing strict firewall rules and network segmentation, limiting inbound traffic to trusted sources only. 3. Enforce strong authentication and authorization controls for system and project admin accounts to reduce the risk of privilege escalation or misuse. 4. Monitor network traffic and logs for unusual outbound requests originating from Kylin servers that could indicate exploitation attempts. 5. Implement web application firewalls (WAFs) with rules designed to detect and block SSRF attack patterns targeting Kylin endpoints. 6. Conduct regular security assessments and penetration testing focusing on SSRF and related vulnerabilities in the analytics environment. 7. Educate system administrators and security teams about SSRF risks and ensure incident response plans include procedures for SSRF exploitation scenarios. 8. Where possible, disable or tightly control any functionality in Kylin that allows server-side HTTP requests to arbitrary URLs or internal resources.