diff --git a/src/HttpResponse.cc b/src/HttpResponse.cc
index f310e083..264f9024 100644
--- a/src/HttpResponse.cc
+++ b/src/HttpResponse.cc
@@ -113,11 +113,11 @@ void HttpResponse::validateResponse() const
 }
 
 std::string HttpResponse::determineFilename(
-    bool content_disposition_default_utf8) const
+    bool contentDispositionUTF8) const
 {
   std::string contentDisposition = util::getContentDispositionFilename(
       httpHeader_->find(HttpHeader::CONTENT_DISPOSITION),
-      content_disposition_default_utf8);
+      contentDispositionUTF8);
   if (contentDisposition.empty()) {
     auto file = httpRequest_->getFile();
     file = util::percentDecode(file.begin(), file.end());
diff --git a/src/HttpResponse.h b/src/HttpResponse.h
index d513ac50..2caffaf1 100644
--- a/src/HttpResponse.h
+++ b/src/HttpResponse.h
@@ -70,7 +70,7 @@ public:
    * this function returns the filename from it.
    * If it is not there, returns the part of filename from the request URL.
    */
-  std::string determineFilename(bool content_disposition_default_utf8) const;
+  std::string determineFilename(bool contentDispositionUTF8) const;
 
   void retrieveCookie();
 
diff --git a/src/usage_text.h b/src/usage_text.h
index 0a124817..e6c18513 100644
--- a/src/usage_text.h
+++ b/src/usage_text.h
@@ -538,9 +538,10 @@
   _(" --use-head[=true|false]      Use HEAD method for the first request to the HTTP\n" \
     "                              server.")
 #define TEXT_CONTENT_DISPOSITION_DEFAULT_UTF8                          \
-  _(" --content-disposition-default-utf8[=true|false] handle filename in\n" \
+  _(" --content-disposition-default-utf8[=true|false] Handle quoted string in\n" \
     "                              Content-Disposition header as UTF-8 instead of\n" \
-    "                              ISO-8859-1.")
+    "                              ISO-8859-1, for example, the filename parameter,\n" \
+    "                              but not the extended version filename*")
 #define TEXT_EVENT_POLL                                                 \
   _(" --event-poll=POLL            Specify the method for polling events.")
 #define TEXT_BT_EXTERNAL_IP                                             \
diff --git a/src/util.cc b/src/util.cc
index c4051e55..bbf6977a 100644
--- a/src/util.cc
+++ b/src/util.cc
@@ -879,7 +879,7 @@ typedef enum {
 
 ssize_t parse_content_disposition(char* dest, size_t destlen,
                                   const char** charsetp, size_t* charsetlenp,
-                                  const char* in, size_t len, bool default_utf8)
+                                  const char* in, size_t len, bool defaultUTF8)
 {
   const char *p = in, *eop = in + len, *mark_first = nullptr,
              *mark_last = nullptr;
@@ -891,7 +891,7 @@ ssize_t parse_content_disposition(char* dest, size_t destlen,
   /* To suppress warnings */
   char* dp = dest;
   size_t dlen = destlen;
-  uint32_t dfa_state = 0;
+  uint32_t dfa_state = UTF8_ACCEPT;
   uint32_t dfa_code = 0;
   uint8_t pctval = 0;
 
@@ -981,7 +981,7 @@ ssize_t parse_content_disposition(char* dest, size_t destlen,
       if (*p == '"') {
         quoted_seen = 0;
         state = CD_QUOTED_STRING;
-        if(default_utf8){
+        if(defaultUTF8){
           dfa_state = UTF8_ACCEPT;
           dfa_code = 0;
         }
@@ -1015,16 +1015,19 @@ ssize_t parse_content_disposition(char* dest, size_t destlen,
         quoted_seen = 1;
       }
       else if (*p == '"' && quoted_seen == 0) {
+        if(defaultUTF8 && dfa_state != UTF8_ACCEPT){
+          return -1;
+        }
         if (in_file_parm) {
           flags |= CD_FILENAME_FOUND;
         }
         state = CD_AFTER_VALUE;
       }
       else {
-        /* TEXT which is OCTET except CTLs, but including LWS. accept
-           ISO-8859-1 chars, or UTF-8 if content-disposition-default-utf8 is set */
+        /* TEXT which is OCTET except CTLs, but including LWS. Accept
+           ISO-8859-1 chars, or UTF-8 if defaultUTF8 is set */
         quoted_seen = 0;
-        if (default_utf8){
+        if (defaultUTF8){
           if (utf8dfa(&dfa_state, &dfa_code, (unsigned char)*p) == UTF8_REJECT) {
             return -1;
           }
@@ -1214,7 +1217,7 @@ ssize_t parse_content_disposition(char* dest, size_t destlen,
 }
 
 std::string getContentDispositionFilename(const std::string& header,
-    bool default_utf8)
+    bool defaultUTF8)
 {
   std::array<char, 1_k> cdval;
   size_t cdvallen = cdval.size();
@@ -1222,14 +1225,14 @@ std::string getContentDispositionFilename(const std::string& header,
   size_t charsetlen;
   ssize_t rv =
       parse_content_disposition(cdval.data(), cdvallen, &charset, &charsetlen,
-                                header.c_str(), header.size(), default_utf8);
+                                header.c_str(), header.size(), defaultUTF8);
   if (rv == -1) {
     return "";
   }
 
   std::string res;
   if ((charset && strieq(charset, charset + charsetlen, "iso-8859-1"))
-      || (!charset && !default_utf8)){
+      || (!charset && !defaultUTF8)){
     res = iso8859p1ToUtf8(cdval.data(), rv);
   }
   else {
diff --git a/src/util.h b/src/util.h
index 314f7918..2fc8ca40 100644
--- a/src/util.h
+++ b/src/util.h
@@ -322,12 +322,15 @@ std::string iso8859p1ToUtf8(const std::string& src);
 // succeeds, or -1. If there is enough room to store filename in
 // |dest|, this function returns -1. If this function returns -1, the
 // |dest|, |*charsetp| and |*charsetlenp| are undefined.
+//
+// It will handle quoted string(as in RFC 7230 section 3.2.6) as
+// ISO-8859-1 by default, or UTF-8 if defaultUTF8 == true.
 ssize_t parse_content_disposition(char* dest, size_t destlen,
                                   const char** charsetp, size_t* charsetlenp,
-                                  const char* in, size_t len, bool default_utf8);
+                                  const char* in, size_t len, bool defaultUTF8);
 
 std::string getContentDispositionFilename(const std::string& header,
-                                          bool default_utf8);
+                                          bool defaultUTF8);
 
 std::string toUpper(std::string src);