diff --git a/src/trix/models/html_parser.coffee b/src/trix/models/html_parser.coffee
index 57b45db1d..8a1bec540 100644
--- a/src/trix/models/html_parser.coffee
+++ b/src/trix/models/html_parser.coffee
@@ -238,7 +238,12 @@ class Trix.HTMLParser extends Trix.BasicObject
 
   parseTrixDataAttribute = (element, name) ->
     try
-     JSON.parse(element.getAttribute("data-trix-#{name}"))
+      data = JSON.parse(element.getAttribute("data-trix-#{name}"))
+
+      if data.contentType == "text/html" && data.content
+        data.content = HTMLSanitizer.sanitize(data.content).getHTML()
+
+      data
     catch
       {}
 
diff --git a/src/trix/models/html_sanitizer.coffee b/src/trix/models/html_sanitizer.coffee
index 87008ebad..d3fabb08e 100644
--- a/src/trix/models/html_sanitizer.coffee
+++ b/src/trix/models/html_sanitizer.coffee
@@ -3,7 +3,7 @@
 class Trix.HTMLSanitizer extends Trix.BasicObject
   DEFAULT_ALLOWED_ATTRIBUTES = "style href src width height class".split(" ")
   DEFAULT_FORBIDDEN_PROTOCOLS = "javascript:".split(" ")
-  DEFAULT_FORBIDDEN_ELEMENTS = "script iframe".split(" ")
+  DEFAULT_FORBIDDEN_ELEMENTS = "script iframe noscript".split(" ")
 
   @sanitize: (html, options) ->
     sanitizer = new this html, options
diff --git a/test/src/system/pasting_test.coffee b/test/src/system/pasting_test.coffee
index b08f5d94a..b3fef6bc0 100644
--- a/test/src/system/pasting_test.coffee
+++ b/test/src/system/pasting_test.coffee
@@ -53,6 +53,34 @@ testGroup "Pasting", template: "editor_empty", ->
         delete window.unsanitized
         done()
 
+    test "paste unsafe html with noscript", (done) ->
+      window.unsanitized = []
+      pasteData =
+        "text/plain": "x",
+        "text/html": """
+          <div><noscript><div class="123</noscript>456<img src=1 onerror=window.unsanitized.push(1)//"></div></noscript></div>
+        """
+
+      pasteContent pasteData, () ->
+        after 20, () ->
+          assert.deepEqual(window.unsanitized, [])
+          delete window.unsanitized
+          done()
+
+    test "paste data-trix-attachment unsafe html", (done) ->
+      window.unsanitized = []
+      pasteData =
+        "text/plain": "x",
+        "text/html": """
+          copy<div data-trix-attachment="{&quot;contentType&quot;:&quot;text/html&quot;,&quot;content&quot;:&quot;&lt;img src=1 onerror=window.unsanitized.push(1)&gt;HELLO123&quot;}"></div>me
+        """
+
+      pasteContent pasteData, ->
+        after 20, ->
+          assert.deepEqual window.unsanitized, []
+          delete window.unsanitized
+          done()
+
   test "prefers plain text when html lacks formatting", (expectDocument) ->
     pasteData =
       "text/html": "<meta charset='utf-8'>a\nb"