diff --git a/rhino/proguard-rules.pro b/rhino/proguard-rules.pro
index 1a2e575b0..4382bdafd 100644
--- a/rhino/proguard-rules.pro
+++ b/rhino/proguard-rules.pro
@@ -26,4 +26,5 @@
 -keep class java.lang.** { *; }
 -keep class java.util.function.** { *; }
 -keep class com.sun.script.javascript.** { *; }
+-keep class org.mozilla.classfile.** { *; }
 -keep class org.mozilla.javascript.** { *; }
\ No newline at end of file