diff --git a/MarkdownParse.java b/MarkdownParse.java
index 2f63d6a92..dc1f19bc6 100644
--- a/MarkdownParse.java
+++ b/MarkdownParse.java
@@ -11,6 +11,9 @@ static int findCloseParen(String markdown, int openParen) {
         int closeParen = openParen + 1;
         int openParenCount = 1;
         while (openParenCount > 0) {
+            if (closeParen >= markdown.length()) {
+                return -1;
+            }
             if (markdown.charAt(closeParen) == '(') {
                 openParenCount++;
             } else if (markdown.charAt(closeParen) == ')') {