cmd/sgblog-comment-add/mail.go | 11 ++++++++++-

diff --git a/cmd/sgblog-comment-add/mail.go b/cmd/sgblog-comment-add/mail.go
index 2af066a81350b540e47524e04461a611b16cbf3aa50c29b2e4aa4bd56ccefdb8..4dec5331e9dce6aef17339f716782cc4d6cd470dfd633ff6609213b141e62cd0 100644
--- a/cmd/sgblog-comment-add/mail.go
+++ b/cmd/sgblog-comment-add/mail.go
@@ -21,6 +21,7 @@ import (
 	"bytes"
 	"encoding/base64"
 	"errors"
+	"fmt"
 	"io"
 	"mime"
 	"mime/multipart"
@@ -74,6 +75,10 @@ 		body, err = processTP(ct, msg.Header.Get(CTE), msg.Body)
 		return
 	}
 	ct, params, err := mime.ParseMediaType(ct)
+	if err != nil {
+		err = fmt.Errorf("can not ParseMediaType: %w", err)
+		return
+	}
 	if ct != "multipart/signed" {
 		err = errors.New("only text/plain and multipart/signed+text/plain Content-Type supported")
 		return
@@ -108,7 +113,11 @@ 			body, err = processTP(ct, part.Header.Get(CTE), part)
 			return
 		}
 		if strings.HasPrefix(ct, "multipart/mixed") {
-			ct, params, err = mime.ParseMediaType(ct)
+			_, params, err = mime.ParseMediaType(ct)
+			if err != nil {
+				err = fmt.Errorf("can not ParseMediaType: %w", err)
+				return
+			}
 			boundary = params["boundary"]
 			if len(boundary) == 0 {
 				err = errors.New("no boundary string")