CVE-2025-30220 identifies an XML External Entity (XXE) processing vulnerability in GeoServer Web Feature Service (WFS) that enables unauthenticated attackers to perform out-of-band data exfiltration of local files and server-side request forgery attacks by exploiting inadequate entity resolution controls in XSD schema handling. This vulnerability affects GeoServer versions prior to 2.27.1, 2.26.0-2.26.2, and versions up to 2.25.6, achieving a CVSS score of 8.2 (High severity) with EPSS percentile of 89.6 indicating extremely high exploit risk for geospatial data platforms and geographic information systems utilizing GeoServer for web mapping services. The vulnerability details reveal that insufficient entity resolution validation in the GeoTools XSD library bypasses GeoServer's AllowListEntityResolver security controls, enabling attackers to trigger parsing of external DTDs and entities through WFS service requests, creating substantial exploit risk for organizations providing public geospatial services and geographic data platforms that process XML-based requests without proper XXE protection mechanisms. The root cause analysis reveals that the vulnerability stems from inadequate entity resolver enforcement in the gt-xsd-core Schemas class where the GeoTools library fails to utilize EntityResolver controls during in-memory XSD schema representation building, classified as CWE-611 (Improper Restriction of XML External Entity Reference). The vulnerability specifically affects XML parsing workflows where the ENTITY_RESOLUTION_ALLOWLIST property restrictions are bypassed during XSD schema processing, enabling attackers to exploit known exploited vulnerabilities targeting XML parsing mechanisms to access sensitive filesystem content including configuration files, credentials, and system files accessible to the GeoServer process. Mitigation steps require immediate upgrading to patched GeoServer versions 2.27.1, 2.26.3, or 2.25.7 which implement proper entity resolution controls in XSD schema handling, or alternatively configure external entity resolution restrictions using the ENTITY_RESOLUTION_ALLOWLIST property for systems unable to upgrade immediately. Organizations should prioritize identifying GeoServer deployments using vulnerable versions, implement strict XML input validation and entity resolution controls for all WFS service endpoints, monitor for suspicious external entity requests and unauthorized file access attempts, validate all XML processing workflows for XXE vulnerabilities, and maintain updated vulnerability database records to track similar XML external entity vulnerabilities that could compromise geospatial platforms through information disclosure attacks and broader security implications for web mapping services processing untrusted XML input data with insufficient entity resolution security controls.