diff --git a/backend/common.go b/backend/common.go
index 8ffb71bc..baa22307 100644
--- a/backend/common.go
+++ b/backend/common.go
@@ -230,6 +230,10 @@ func ParseCopySourceRange(size int64, acceptRange string) (int64, int64, error)
 // ParseCopySource parses x-amz-copy-source header and returns source bucket,
 // source object, versionId, error respectively
 func ParseCopySource(copySourceHeader string) (string, string, string, error) {
+	if copySourceHeader == "" {
+		return "", "", "", s3err.GetInvalidArgumentErr(s3err.InvalidArgCopySourceBucket, copySourceHeader)
+	}
+
 	if copySourceHeader[0] == '/' {
 		copySourceHeader = copySourceHeader[1:]
 	}
diff --git a/backend/common_test.go b/backend/common_test.go
index 993a7d8d..fa69eb66 100644
--- a/backend/common_test.go
+++ b/backend/common_test.go
@@ -223,6 +223,15 @@ func TestParseCopySource(t *testing.T) {
 			wantErr:          true,
 			wantErrValue:     s3err.GetInvalidArgumentErr(s3err.InvalidArgCopySourceEncoding, "mybucket/object%ZZ"),
 		},
+		{
+			name:             "empty string",
+			copySourceHeader: "",
+			wantBucket:       "",
+			wantObject:       "",
+			wantVersionId:    "",
+			wantErr:          true,
+			wantErrValue:     s3err.GetInvalidArgumentErr(s3err.InvalidArgCopySourceBucket, ""),
+		},
 		{
 			name:             "missing object",
 			copySourceHeader: "mybucket",