diff --git a/fetch/security/dangling-markup/META.yml b/fetch/security/dangling-markup/META.yml
new file mode 100644
index 000000000..6d3b62273
--- /dev/null
+++ b/fetch/security/dangling-markup/META.yml
@@ -0,0 +1,82 @@
+links:
+- product: firefox
+  results:
+  - subtest: <iframe id="dangling"\n        src="data:text/html,\n            <img\n              onload='window.parent.postMessage(&quot;loaded&quot;,
+      &quot;*&quot;);'\n              onerror='window.parent.postMessage(&quot;error&quot;,
+      &quot;*&quot;);'\n              src='http://web-platform.test:8000/images/gr&#10;een-256x256.png?&lt;'>\n        ">\n     </iframe>
+    test: dangling-markup-mitigation-data-url.tentative.sub.html
+  - subtest: <iframe id="dangling"\n        src="     data:text/html,\n            <img\n              onload='window.parent.postMessage(&quot;loaded&quot;,
+      &quot;*&quot;);'\n              onerror='window.parent.postMessage(&quot;error&quot;,
+      &quot;*&quot;);'\n              src='http://web-platform.test:8000/images/gr&#10;een-256x256.png?&lt;'>\n        ">\n     </iframe>
+    test: dangling-markup-mitigation-data-url.tentative.sub.html
+  - subtest: <iframe id="dangling"\n        src="\ndata:text/html,\n            <img\n              onload='window.parent.postMessage(&quot;loaded&quot;,
+      &quot;*&quot;);'\n              onerror='window.parent.postMessage(&quot;error&quot;,
+      &quot;*&quot;);'\n              src='http://web-platform.test:8000/images/gr&#10;een-256x256.png?&lt;'>\n        ">\n     </iframe>
+    test: dangling-markup-mitigation-data-url.tentative.sub.html
+  - subtest: <iframe id="dangling"\n        src="&#10;data:text/html,\n            <img\n              onload='window.parent.postMessage(&quot;loaded&quot;,
+      &quot;*&quot;);'\n              onerror='window.parent.postMessage(&quot;error&quot;,
+      &quot;*&quot;);'\n              src='http://web-platform.test:8000/images/gr&#10;een-256x256.png?&lt;'>\n        ">\n     </iframe>
+    test: dangling-markup-mitigation-data-url.tentative.sub.html
+  - subtest: <iframe id="dangling"\n        src="\tdata:text/html,\n            <img\n              onload='window.parent.postMessage(&quot;loaded&quot;,
+      &quot;*&quot;);'\n              onerror='window.parent.postMessage(&quot;error&quot;,
+      &quot;*&quot;);'\n              src='http://web-platform.test:8000/images/gr&#10;een-256x256.png?&lt;'>\n        ">\n     </iframe>
+    test: dangling-markup-mitigation-data-url.tentative.sub.html
+  - subtest: <iframe id="dangling"\n        src="\rdata:text/html,\n            <img\n              onload='window.parent.postMessage(&quot;loaded&quot;,
+      &quot;*&quot;);'\n              onerror='window.parent.postMessage(&quot;error&quot;,
+      &quot;*&quot;);'\n              src='http://web-platform.test:8000/images/gr&#10;een-256x256.png?&lt;'>\n        ">\n     </iframe>
+    test: dangling-markup-mitigation-data-url.tentative.sub.html
+  - subtest: 'Fetch: /images/gre\nen-1x1.png?img=<'
+    test: dangling-markup-mitigation.tentative.html
+  - subtest: 'Fetch: /images/gre\ren-1x1.png?img=<'
+    test: dangling-markup-mitigation.tentative.html
+  - subtest: 'Fetch: /images/gre\ten-1x1.png?img=<'
+    test: dangling-markup-mitigation.tentative.html
+  - subtest: 'Fetch: /images/green-1x1.png?<\n=block'
+    test: dangling-markup-mitigation.tentative.html
+  - subtest: 'Fetch: /images/green-1x1.png?<\r=block'
+    test: dangling-markup-mitigation.tentative.html
+  - subtest: 'Fetch: /images/green-1x1.png?<\t=block'
+    test: dangling-markup-mitigation.tentative.html
+  - subtest: <img id="dangling" src="/images/green-1x1.png?img=&#10;&lt;b">
+    test: dangling-markup-mitigation.tentative.html
+  - subtest: <img id="dangling" src="/images/green-1x1.png?img=&lt;&#10;b">
+    test: dangling-markup-mitigation.tentative.html
+  - subtest: '\n      <img id="dangling" src="/images/green-1x1.png?img=\n        &lt;\n        &#10;b\n      ">\n    '
+    test: dangling-markup-mitigation.tentative.html
+  - subtest: Should not load audio with dangling markup in URL
+    test: media.html
+  - subtest: Should not load video with dangling markup in URL
+    test: media.html
+  - subtest: '      <form action="/resource-timing/resources/document-navigated.html"
+      method="post">        <input type="submit">        <select name="dangling"><option>    '
+    test: option.html
+  - subtest: '      <div>        <form action="/resource-timing/resources/document-navigated.html"
+      method="post">          <input type="submit">          <select name="dangling"><option>    '
+    test: option.html
+  - subtest: '      <form action="/resource-timing/resources/document-navigated.html"
+      method="post" id="form">        <input type="submit">      </form>      <select
+      name="dangling" form="form"><option>    '
+    test: option.html
+  - subtest: '      <form action="/resource-timing/resources/document-navigated.html"
+      method="post">        <input type="submit">        <select name="dangling"><option
+      label="yay">    '
+    test: option.html
+  - subtest: '      <div>        <form action="/resource-timing/resources/document-navigated.html"
+      method="post">          <input type="submit">          <select name="dangling"><option
+      label="yay">    '
+    test: option.html
+  - subtest: '      <form action="/resource-timing/resources/document-navigated.html"
+      method="post" id="form">        <input type="submit">      </form>      <select
+      name="dangling" form="form"><option label="yay">    '
+    test: option.html
+  - subtest: '      <form action="/resource-timing/resources/document-navigated.html"
+      method="post">        <input type="submit">        <textarea name="dangling">    '
+    test: textarea.html
+  - subtest: '      <div>        <form action="/resource-timing/resources/document-navigated.html"
+      method="post">          <input type="submit">          <textarea name="dangling">    '
+    test: textarea.html
+  - subtest: '      <form action="/resource-timing/resources/document-navigated.html"
+      method="post" id="form">        <input type="submit">      </form>      <textarea
+      name="dangling" form="form">    '
+    test: textarea.html
+  url: https://bugzilla.mozilla.org/show_bug.cgi?id=1873224