diff --git a/src/pngv3.ts b/src/pngv3.ts
index 8e9c88a..b04c1b8 100644
--- a/src/pngv3.ts
+++ b/src/pngv3.ts
@@ -179,7 +179,7 @@ const has_embed = async (png: Buffer) => {
                         return true;
                     if (buff.slice(4, 4 + CUM6.length).equals(CUM6)) {
                         const passed = buff.slice(4 + CUM6.length).toString();
-                        return !!passed.match(/[0-9a-zA-Z+/]+/g);
+                        return !!passed.match(/^[0-9a-zA-Z+/=]+$/g);
                     }
                     break;
                 case 'IDAT':