diff --git a/config/src/main/java/com/typesafe/config/waterdrop/impl/PathParser.java b/config/src/main/java/com/typesafe/config/waterdrop/impl/PathParser.java
index 1edf039f3..191dc9e85 100644
--- a/config/src/main/java/com/typesafe/config/waterdrop/impl/PathParser.java
+++ b/config/src/main/java/com/typesafe/config/waterdrop/impl/PathParser.java
@@ -193,7 +193,7 @@ private static Collection<Token> splitTokenOnPeriod(Token t, ConfigSyntax flavor
             splitTokens.add(Tokens.newUnquotedText(t.origin(), ConfigParseOptions.pathTokenSeparator));
         }
 
-        if (! tokenText.substring(tokenText.length() - ConfigParseOptions.pathTokenSeparator.length(), tokenText.length()).equals(ConfigParseOptions.pathTokenSeparator)) {
+        if (tokenText.length() < ConfigParseOptions.pathTokenSeparator.length() || ! tokenText.substring(tokenText.length() - ConfigParseOptions.pathTokenSeparator.length(), tokenText.length()).equals(ConfigParseOptions.pathTokenSeparator)) {
             splitTokens.remove(splitTokens.size() - 1);
         }