diff --git a/ChangeLog b/ChangeLog
index eeee7edb23..d676d385c6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Tue Dec 30 13:16:56 2014  Martin Duerst  <bernhard+git@lsmod.de>
+
+	* lib/uri/common.rb: Initialize HTML5ASCIIINCOMPAT to empty Array
+	  to avoid error during bootstrap when encodings are not yet defined.
+	  [Bug #10678]
+
 Tue Dec 30 09:29:26 2014  Bernhard M. Wiedemann  <bernhard+git@lsmod.de>
 
 	* ext/dbm/dbm.c (Init_dbm): [DOC] as UNIX permissions are octal
diff --git a/lib/uri/common.rb b/lib/uri/common.rb
index facca4b08b..20cd0f9b62 100644
--- a/lib/uri/common.rb
+++ b/lib/uri/common.rb
@@ -346,8 +346,8 @@ module URI
   TBLDECWWWCOMP_['+'] = ' '
   TBLDECWWWCOMP_.freeze
 
-  HTML5ASCIIINCOMPAT = [Encoding::UTF_7, Encoding::UTF_16BE, Encoding::UTF_16LE,
-    Encoding::UTF_32BE, Encoding::UTF_32LE] # :nodoc:
+  HTML5ASCIIINCOMPAT = defined? Encoding::UTF_7 ? [Encoding::UTF_7, Encoding::UTF_16BE, Encoding::UTF_16LE,
+    Encoding::UTF_32BE, Encoding::UTF_32LE] : [] # :nodoc:
 
   # Encode given +str+ to URL-encoded form data.
   #