DeleteObjects with recent AWS SDK returns error "Missing required header for this request: Content-MD5"

[pacoteinnov]

Summary

The recent AWS SDK have changes that prevent the use of the multiple delete objects API to be used with ECS.
A "Missing required header for this request: Content-MD5" error is sent by the server.

Steps

// Install latest AWSSDK.S3 nuget package

IAmazonS3 s3Client = new AmazonS3Client();

List<KeyVersion> objectsToDelete =
    new()
    {
        new KeyVersion { Key = "file1.txt" },
        new KeyVersion { Key = "file2.jpg" }
    };

DeleteObjectsRequest deleteObjectsRequest =
    new()
    {
        BucketName = bucketName,
        Objects = objectsToDelete
    };

// The following calls will throw a "Missing required header for this request: Content-MD5" error.
DeleteObjectsResponse response = await s3Client.DeleteObjectsAsync(deleteObjectsRequest);

Notes

Below the headers sent to the server by the AWS SDK.

[0]  {[Content-Type, application/xml]}
[1]  {[amz-sdk-invocation-id, a06903e6-8b00-4333-bd4b-1918a0ae7408]}
[2]  {[amz-sdk-request, attempt=1; max=3]}
[3]  {[x-amz-checksum-crc32, FhWI9w==]}
[4]  {[x-amz-sdk-checksum-algorithm, CRC32]}
[5]  {[host, <REDACTED>]}
[6]  {[X-Amz-Date, 20250625T211545Z]}
[7]  {[X-Amz-Content-SHA256, bda51140d0b9e1dbabaef5dea2f23d1bd3a2da31ef1f3a24da04f2972a3dae57]}
[8]  {[Authorization, AWS4-HMAC-SHA256 Credential=<REDACTED>, SignedHeaders=content-type;host;x-amz-checksum-crc32;x-amz-content-sha256;x-amz-date;x-amz-sdk-checksum-algorithm, Signature=<REDACTED>]}
[9]  {[User-Agent, aws-sdk-dotnet-coreclr/4.0.3.0 ua/2.1 os/windows#10.0.26100.0 md/ARCH#X64 lang/.NET_Core#8.0.17 md/aws-sdk-dotnet-core#4.0.0.13 api/S3#4.0.3.0 md/ClientAsync cfg/init-coll#0 m/b,P,g,E,U,Z]}
[10]  {[Content-Length, 142]}

References

See Minio issue (fixed): minio/minio#20845
Related AWS .NET SDK issue (fixed): aws/aws-sdk-net#3641
Related AWS Go SDK issue: aws/aws-sdk-go-v2#2960