diff --git a/lib/webrick/httputils.rb b/lib/webrick/httputils.rb
index ea67fdb..92f3044 100644
--- a/lib/webrick/httputils.rb
+++ b/lib/webrick/httputils.rb
@@ -178,12 +178,12 @@ def parse_header(raw)
           field.downcase!
           header[field] = HEADER_CLASSES[field].new unless header.has_key?(field)
           header[field] << value
-        when /^\s+([^\r\n\0]*?)\r\n/om
+        when /^[ \t]+([^\r\n\0]*?)\r\n/om
           unless field
             raise HTTPStatus::BadRequest, "bad header '#{line}'."
           end
           value = line
-          value.lstrip!
+          value.gsub!(/\A[ \t]+/, '')
           value.slice!(-2..-1)
           header[field][-1] << " " << value
         else
@@ -191,7 +191,10 @@ def parse_header(raw)
         end
       }
       header.each{|key, values|
-        values.each(&:strip!)
+        values.each{|value|
+          value.gsub!(/\A[ \t]+/, '')
+          value.gsub!(/[ \t]+\z/, '')
+        }
       }
       header
     end
@@ -202,7 +205,7 @@ def parse_header(raw)
 
     def split_header_value(str)
       str.scan(%r'\G((?:"(?:\\.|[^"])+?"|[^",]++)+)
-                    (?:,\s*|\Z)'xn).flatten
+                    (?:,[ \t]*|\Z)'xn).flatten
     end
     module_function :split_header_value
 
@@ -230,9 +233,9 @@ def parse_range_header(ranges_specifier)
     def parse_qvalues(value)
       tmp = []
       if value
-        parts = value.split(/,\s*/)
+        parts = value.split(/,[ \t]*/)
         parts.each {|part|
-          if m = %r{^([^\s,]+?)(?:;\s*q=(\d+(?:\.\d+)?))?$}.match(part)
+          if m = %r{^([^ \t,]+?)(?:;[ \t]*q=(\d+(?:\.\d+)?))?$}.match(part)
             val = m[1]
             q = (m[2] or 1).to_f
             tmp.push([val, q])
@@ -331,8 +334,8 @@ def <<(str)
         elsif str == CRLF
           @header = HTTPUtils::parse_header(@raw_header.join)
           if cd = self['content-disposition']
-            if /\s+name="(.*?)"/ =~ cd then @name = $1 end
-            if /\s+filename="(.*?)"/ =~ cd then @filename = $1 end
+            if /[ \t]+name="(.*?)"/ =~ cd then @name = $1 end
+            if /[ \t]+filename="(.*?)"/ =~ cd then @filename = $1 end
           end
         else
           @raw_header << str
diff --git a/test/webrick/test_httprequest.rb b/test/webrick/test_httprequest.rb
index 6088f18..ad00d60 100644
--- a/test/webrick/test_httprequest.rb
+++ b/test/webrick/test_httprequest.rb
@@ -118,6 +118,27 @@ def test_bare_lf_header
     }
   end
 
+  def test_header_vt_ff_whitespace
+    msg = <<~HTTP
+      GET / HTTP/1.1\r
+      Foo: \x0b1\x0c\r
+      \r
+    HTTP
+    req = WEBrick::HTTPRequest.new(WEBrick::Config::HTTP)
+    req.parse(StringIO.new(msg.gsub(/^ {6}/, "")))
+    assert_equal("\x0b1\x0c", req["Foo"])
+
+    msg = <<~HTTP
+      GET / HTTP/1.1\r
+      Foo: \x0b1\x0c\r
+       \x0b2\x0c\r
+      \r
+    HTTP
+    req = WEBrick::HTTPRequest.new(WEBrick::Config::HTTP)
+    req.parse(StringIO.new(msg.gsub(/^ {6}/, "")))
+    assert_equal("\x0b1\x0c \x0b2\x0c", req["Foo"])
+  end
+
   def test_bare_cr_request_line
     msg = <<~HTTP.gsub("\n", "\r\n")
       GET / HTTP/1.1\r\r