diff --git a/lib/sanitizer.rb b/lib/sanitizer.rb
index 43ad40fb..bfdc711c 100644
--- a/lib/sanitizer.rb
+++ b/lib/sanitizer.rb
@@ -48,9 +48,9 @@ module Sanitizer
   svg_attributes = %w[accent-height accumulate additive alphabetic
        arabic-form ascent attributeName attributeType baseProfile bbox begin
        by calcMode cap-height class color color-rendering content cx cy d dx
-       dy descent display dur end fill fill-rule font-family font-size
-       font-stretch font-style font-variant font-weight from fx fy g1 g2
-       glyph-name gradientUnits hanging height horiz-adv-x horiz-origin-x id
+       dy descent display dur end fill fill-opacity fill-rule font-family 
+       font-size font-stretch font-style font-variant font-weight from fx fy g1 
+       g2 glyph-name gradientUnits hanging height horiz-adv-x horiz-origin-x id
        ideographic k keyPoints keySplines keyTimes lang marker-end
        marker-mid marker-start markerHeight markerUnits markerWidth
        mathematical max min name offset opacity orient origin
diff --git a/vendor/plugins/HTML5lib/lib/html5/sanitizer.rb b/vendor/plugins/HTML5lib/lib/html5/sanitizer.rb
index a36148f8..f9bf445a 100644
--- a/vendor/plugins/HTML5lib/lib/html5/sanitizer.rb
+++ b/vendor/plugins/HTML5lib/lib/html5/sanitizer.rb
@@ -57,9 +57,9 @@ module HTML5
     SVG_ATTRIBUTES = %w[accent-height accumulate additive alphabetic
        arabic-form ascent attributeName attributeType baseProfile bbox begin
        by calcMode cap-height class color color-rendering content cx cy d dx
-       dy descent display dur end fill fill-rule font-family font-size
-       font-stretch font-style font-variant font-weight from fx fy g1 g2
-       glyph-name gradientUnits hanging height horiz-adv-x horiz-origin-x id
+       dy descent display dur end fill fill-opacity fill-rule font-family
+       font-size font-stretch font-style font-variant font-weight from fx fy g1
+       g2 glyph-name gradientUnits hanging height horiz-adv-x horiz-origin-x id
        ideographic k keyPoints keySplines keyTimes lang marker-end
        marker-mid marker-start markerHeight markerUnits markerWidth
        mathematical max min name offset opacity orient origin