CVE-2026-3415: XML External Entity (XXE) Injection via Schema Validation in Multiple WSO2 Products Allows File Reading and Denial of Service

The XML and schema validation functionalities within the SchemaValidator Mediator process XML input as part of validation flows. Under certain conditions, the XML parser allows the resolution of external entities when handling user-supplied XML content during validation operations. This behavior can occur when an attacker supplies crafted XML payloads to the relevant mediator flows with sufficient privileges.

Successful exploitation may allow a highly privileged actor to read files accessible within the server hosting the affected product. Additionally, it may be possible to trigger outbound requests to unintended internal or external locations, depending on the server environment and network configuration. Specially crafted XML payloads can also lead to excessive resource consumption during parsing, impacting the availability of the product.