diff --git a/src/backend/utils/adt/quote.c b/src/backend/utils/adt/quote.c
index d1336b4df1b..e43179059af 100644
--- a/src/backend/utils/adt/quote.c
+++ b/src/backend/utils/adt/quote.c
@@ -107,7 +107,7 @@ quote_literal_cstr(const char *rawstr)
 
 	len = strlen(rawstr);
 	/* We make a worst-case result area; wasting a little space is OK */
-	result = palloc(len * 2 + 3);
+	result = palloc(len * 2 + 3 + 1);
 
 	newlen = quote_literal_internal(result, rawstr, len);
 	result[newlen] = '\0';