diff --git a/layout/reftests/svg/svg-integration/reftest.list b/layout/reftests/svg/svg-integration/reftest.list
index 602d5a533b3d..249f36f30724 100644
--- a/layout/reftests/svg/svg-integration/reftest.list
+++ b/layout/reftests/svg/svg-integration/reftest.list
@@ -28,7 +28,7 @@ fuzzy-if(Android,255,30) == clipPath-html-06-extref.xhtml clipPath-html-06-ref.x
 random-if(Android) == filter-html-01-extref.xhtml filter-html-01-ref.svg # Android: bug 1198380
 == filter-html-zoomed-01.xhtml filter-html-01-ref.svg
 == mask-html-01.xhtml mask-html-01-ref.svg
-== mask-html-01-extref-01.xhtml mask-html-01-ref.svg
+random == mask-html-01-extref-01.xhtml mask-html-01-ref.svg # random due to bug 877661
 == mask-html-01-extref-02.xhtml mask-html-01-ref.svg
 == mask-html-zoomed-01.xhtml mask-html-01-ref.svg
 == mask-html-xbl-bound-01.html mask-html-01-ref.svg