diff --git a/source/Handlebars.Test/IssueTests.cs b/source/Handlebars.Test/IssueTests.cs
index 6c1402d7..31136117 100644
--- a/source/Handlebars.Test/IssueTests.cs
+++ b/source/Handlebars.Test/IssueTests.cs
@@ -723,5 +723,15 @@ public void LastLetterCutOff()
 
             Assert.Equal("abcd", templateOutput);
         }
+
+        // Issue: https://github.com/Handlebars-Net/Handlebars.Net/issues/535
+        // Issue refers to invalid template causing OutOfMemoryException
+        [Fact]
+        public void UnrecognisedExpressionThrowsOutOfMemoryException()
+        {
+            var source = "{{Name | invalid}}";
+
+            Assert.Throws<HandlebarsCompilerException>(()=> Handlebars.Compile(source));
+        }
     }
 }
\ No newline at end of file
diff --git a/source/Handlebars/Compiler/Lexer/Parsers/BlockParamsParser.cs b/source/Handlebars/Compiler/Lexer/Parsers/BlockParamsParser.cs
index 4b861705..aedc18f0 100644
--- a/source/Handlebars/Compiler/Lexer/Parsers/BlockParamsParser.cs
+++ b/source/Handlebars/Compiler/Lexer/Parsers/BlockParamsParser.cs
@@ -23,7 +23,7 @@ private static string AccumulateWord(ExtendedStringReader reader)
                 
                 reader.Read();
             
-                while (reader.Peek() != '|')
+                while (reader.Peek() != '|' && reader.Peek() != -1)
                 {
                     buffer.Append((char) reader.Read());
                 }