diff --git a/codec.go b/codec.go
index 3bfe59ed76659d662998cb005834894b77b72355..30873f57cf24836051995e4e85762e2b2e3c1e88 100644
--- a/codec.go
+++ b/codec.go
@@ -148,7 +148,7 @@ func (i *inputScanner) parseQuotedString() (string, error) {
 }
 
 func (i *inputScanner) parseBase64String() (string, error) {
-	data := i.parseUntilOrEOF(' ')
+	data := bytes.TrimRight(i.parseUntilOrEOF(' '), "=")
 	out := make([]byte, base64.RawURLEncoding.DecodedLen(len(data)))
 	_, err := base64.RawURLEncoding.Decode(out, data)
 	if err != nil {