CVE-2021-21390 log

Severity Medium
Remote Yes
Type Man-in-the-middle
In MinIO before version RELEASE.2021-03-17T02-33-02Z, there is a vulnerability which enables man-in-the-middle (MITM) modification of request bodies that are meant to have integrity guaranteed by chunk signatures. In a PUT request using the aws-chunked encoding, MinIO ordinarily verifies signatures at the end of a chunk. This check can be skipped if the client sends a false chunk size that is much greater than the actual data sent: the server accepts and completes the request without ever reaching the end of the chunk and thereby without ever checking the chunk signature. This is fixed in version RELEASE.2021-03-17T02-33-02Z.
Group Package Affected Fixed Severity Status Ticket
AVG-1715 minio 2021.03.04-1 2021.03.17-1 Medium Fixed

As a workaround one can avoid using "aws-chunked" encoding-based chunk signature upload requests and instead use TLS. MinIO SDKs automatically disable chunked encoding signature when the server endpoint is configured with TLS.