Apache Arrow C++, PyArrow: Parquet file-controlled KMS URL is forwarded to pluggable KmsClient that skips host validation
Pass-through of unvalidated KMS URLs to KMS clients in Apache C++ Parquet and PyArrow versions 4.0.0 to 25.0.1. This affects users who read Parquet files and configure Parquet decryption properties with a KmsClient implementation. On the reader side, the KMS URL can be application-controlled (specified in the KmsConnectionConfig) or file-controlled. If the user does not leverage application control for this parameter, a file-controlled KMS URL is forwarded to a pluggable KmsClient implementation. If the KMS implementation does not perform host validation and makes use of the provided KMS URL, a KMS token can be sent to a malicious ho