CVE-2025-29847 is a vulnerability in Apache Linkis, an open-source data integration and governance platform widely used for big data analytics. The flaw exists in the JDBC engine and data source functionality, where the URL parameter on the frontend can be subjected to multiple rounds of URL encoding. This improper input validation (CWE-20) allows attackers to bypass the system's security checks by encoding the URL multiple times, which the system fails to decode properly before processing. As a result, attackers can craft malicious JDBC parameters that grant unauthorized access to system files, potentially exposing sensitive data. The vulnerability affects Apache Linkis versions 1.3.0 through 1.7.0. The issue stems from insufficient sanitization and decoding of connection strings containing the '%' character, which is used in URL encoding. The Apache Software Foundation addressed this by implementing continuous URL decoding checks and released a patched version 1.8.0. The vulnerability has a CVSS v3.1 base score of 7.5, indicating high severity due to its network attack vector, low attack complexity, no privileges required, no user interaction, and a high impact on confidentiality. There are no known exploits in the wild at this time, but the potential for unauthorized file access makes this a significant risk for affected deployments.

For European organizations, this vulnerability poses a significant risk to the confidentiality of sensitive data managed or processed via Apache Linkis, particularly in sectors relying heavily on big data analytics such as finance, telecommunications, healthcare, and government. Unauthorized access to system files could lead to data breaches, exposure of intellectual property, or leakage of personally identifiable information (PII), potentially violating GDPR and other data protection regulations. The vulnerability does not affect system integrity or availability directly but could be leveraged as a foothold for further attacks. Organizations using affected versions in production environments may face compliance risks, reputational damage, and operational disruptions if exploited. Since exploitation requires no authentication and can be performed remotely over the network, the threat surface is broad. European entities with complex data pipelines integrating multiple data sources via Apache Linkis should prioritize remediation to prevent unauthorized data disclosure.

1. Upgrade Apache Linkis to version 1.8.0 or later, where the vulnerability is fully patched. 2. In environments where immediate upgrade is not feasible, implement strict input validation and sanitization on all frontend URL parameters, ensuring that multiple URL encodings are properly decoded and checked before processing. 3. Restrict network access to the Apache Linkis JDBC engine to trusted internal networks or via VPN to reduce exposure. 4. Monitor logs for unusual JDBC connection attempts or malformed URL parameters indicative of exploitation attempts. 5. Employ Web Application Firewalls (WAFs) with custom rules to detect and block suspicious URL encoding patterns targeting the JDBC parameters. 6. Conduct regular security audits and penetration testing focused on data source integrations to identify similar input validation weaknesses. 7. Educate development and operations teams about secure coding practices related to input validation and URL encoding/decoding processes.