diff --git a/Libraries/LibHTML/Parser/CSSParser.cpp b/Libraries/LibHTML/Parser/CSSParser.cpp
index e12cbd20ec..5ce42df1cb 100644
--- a/Libraries/LibHTML/Parser/CSSParser.cpp
+++ b/Libraries/LibHTML/Parser/CSSParser.cpp
@@ -345,6 +345,10 @@ public:
 
     void parse_rule()
     {
+        consume_whitespace_or_comments();
+        if (index >= css.length())
+            return;
+
         // FIXME: We ignore @media rules for now.
         if (next_is("@media")) {
             while (peek() != '{')