diff --git a/lexer.cpp b/lexer.cpp
index 071f00623e..92c2399398 100644
--- a/lexer.cpp
+++ b/lexer.cpp
@@ -270,6 +270,9 @@ void lexer::read(token &out) {
             return;
         }
 
+        // In order for strcmp to work, we need to null-terminate the string.
+        chars.push_back('\0');
+
         if (!strcmp(&chars[0], "version")) {
             out.asDirective.type = directive::kVersion;