diff --git a/CHANGELOG.md b/CHANGELOG.md
index cf006239b34..16335c65314 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,10 @@ The version headers in this history reflect the versions of Apollo Server itself
 
 ## vNEXT
 
+## v3.10.1
+
+- ⚠️ **SECURITY**: The default landing page contained HTML to display a sample `curl` command which is made visible if the full landing page bundle could not be fetched from Apollo's CDN. The server's URL is directly interpolated into this command inside the browser from `window.location.href`. On some older browsers such as IE11, this value is not URI-encoded. On such browsers, opening a malicious URL pointing at an Apollo Router could cause execution of attacker-controlled JavaScript. In this release, the fallback page does not display a `curl` command. More details are available at the [security advisory](https://github.com/apollographql/apollo-server/security/advisories/GHSA-2fvv-qxrq-7jq6).
+- Improve error message when both a graph ref and a graph variant are specified. [PR #6709](https://github.com/apollographql/apollo-server/pull/6709)
 - Fix the TypeScript declaration of the `fieldLevelInstrumentation` option to `ApolloServerPluginUsageReporting` to show that the function may return a number in addition to a boolean. This now matches the implementation and docs. [PR #6763](https://github.com/apollographql/apollo-server/pull/6763)
 
 ## v3.10.0
diff --git a/packages/apollo-server-core/src/plugin/landingPage/__tests__/getEmbeddedExplorerHTML.test.ts b/packages/apollo-server-core/src/plugin/landingPage/__tests__/getEmbeddedExplorerHTML.test.ts
index d0f4972648b..7ae2afbb304 100644
--- a/packages/apollo-server-core/src/plugin/landingPage/__tests__/getEmbeddedExplorerHTML.test.ts
+++ b/packages/apollo-server-core/src/plugin/landingPage/__tests__/getEmbeddedExplorerHTML.test.ts
@@ -29,6 +29,14 @@ describe('Embedded Explorer Landing Page Config HTML', () => {
         graphRef: 'graph@current',
       };
     expect(getEmbeddedExplorerHTML(version, config)).toMatchInlineSnapshot(`
+      <div class="fallback">
+        <h1>
+          Welcome to Apollo Server
+        </h1>
+        <p>
+          Apollo Explorer cannot be loaded; it appears that you might be offline.
+        </p>
+      </div>
       <style>
         iframe {
           background-color: white;
@@ -59,6 +67,14 @@ describe('Embedded Explorer Landing Page Config HTML', () => {
         graphRef: 'graph@current',
       };
     expect(getEmbeddedExplorerHTML(version, config)).toMatchInlineSnapshot(`
+      <div class="fallback">
+        <h1>
+          Welcome to Apollo Server
+        </h1>
+        <p>
+          Apollo Explorer cannot be loaded; it appears that you might be offline.
+        </p>
+      </div>
       <style>
         iframe {
           background-color: white;
diff --git a/packages/apollo-server-core/src/plugin/landingPage/__tests__/getEmbeddedSandboxHTML.test.ts b/packages/apollo-server-core/src/plugin/landingPage/__tests__/getEmbeddedSandboxHTML.test.ts
index 08a70cf2f91..97371c92b5d 100644
--- a/packages/apollo-server-core/src/plugin/landingPage/__tests__/getEmbeddedSandboxHTML.test.ts
+++ b/packages/apollo-server-core/src/plugin/landingPage/__tests__/getEmbeddedSandboxHTML.test.ts
@@ -20,6 +20,14 @@ describe('Landing Page Config HTML', () => {
       embed: true,
     };
     expect(getEmbeddedSandboxHTML(version, config)).toMatchInlineSnapshot(`
+      <div class="fallback">
+        <h1>
+          Welcome to Apollo Server
+        </h1>
+        <p>
+          Apollo Sandbox cannot be loaded; it appears that you might be offline.
+        </p>
+      </div>
       <style>
         iframe {
           background-color: white;
@@ -49,6 +57,14 @@ describe('Landing Page Config HTML', () => {
       embed: true,
     };
     expect(getEmbeddedSandboxHTML(version, config)).toMatchInlineSnapshot(`
+      <div class="fallback">
+        <h1>
+          Welcome to Apollo Server
+        </h1>
+        <p>
+          Apollo Sandbox cannot be loaded; it appears that you might be offline.
+        </p>
+      </div>
       <style>
         iframe {
           background-color: white;
diff --git a/packages/apollo-server-core/src/plugin/landingPage/default/index.ts b/packages/apollo-server-core/src/plugin/landingPage/default/index.ts
index ac9b4ab163b..9e90b7a4548 100644
--- a/packages/apollo-server-core/src/plugin/landingPage/default/index.ts
+++ b/packages/apollo-server-core/src/plugin/landingPage/default/index.ts
@@ -101,6 +101,10 @@ export const getEmbeddedExplorerHTML = (
     };
 
   return `
+<div class="fallback">
+  <h1>Welcome to Apollo Server</h1>
+  <p>Apollo Explorer cannot be loaded; it appears that you might be offline.</p>
+</div>
 <style>
   iframe {
     background-color: white;
@@ -129,6 +133,10 @@ export const getEmbeddedSandboxHTML = (
   config: LandingPageConfig,
 ) => {
   return `
+<div class="fallback">
+  <h1>Welcome to Apollo Server</h1>
+  <p>Apollo Sandbox cannot be loaded; it appears that you might be offline.</p>
+</div>
 <style>
   iframe {
     background-color: white;
@@ -162,6 +170,10 @@ const getNonEmbeddedLandingPageHTML = (
   const encodedConfig = encodeConfig(config);
 
   return `
+ <div class="fallback">
+  <h1>Welcome to Apollo Server</h1>
+  <p>The full landing page cannot be loaded; it appears that you might be offline.</p>
+</div>
 <script>window.landingPage = ${encodedConfig};</script>
 <script src="https://apollo-server-landing-page.cdn.apollographql.com/${version}/static/js/main.js"></script>`;
 };
@@ -224,15 +236,6 @@ function ApolloServerPluginLandingPageDefault(
           100% {opacity:1; }
         }
       </style>
-      <div class="fallback">
-        <h1>Welcome to Apollo Server</h1>
-        <p>It appears that you might be offline. POST to this endpoint to query your graph:</p>
-        <code style="white-space: pre;">
-curl --request POST \\
-  --header 'content-type: application/json' \\
-  --url '<script>document.write(window.location.href)</script>' \\
-  --data '{"query":"query { __typename }"}'</code>
-      </div>
     ${
       config.embed
         ? 'graphRef' in config && config.graphRef