diff --git a/netwerk/protocol/http/HttpBaseChannel.cpp b/netwerk/protocol/http/HttpBaseChannel.cpp
index 7311f90d1156..05949c9069ba 100644
--- a/netwerk/protocol/http/HttpBaseChannel.cpp
+++ b/netwerk/protocol/http/HttpBaseChannel.cpp
@@ -4787,7 +4787,7 @@ nsresult HttpBaseChannel::SetupReplacementChannel(nsIURI* newURI,
       realChannel->SetTopWindowURI(mTopWindowURI);
 
       realChannel->StoreTaintedOriginFlag(
-          ShouldTaintReplacementChannelOrigin(newURI));
+          ShouldTaintReplacementChannelOrigin(newChannel, redirectFlags));
     }
 
     // update the DocumentURI indicator since we are being redirected.
@@ -4864,20 +4864,29 @@ nsresult HttpBaseChannel::SetupReplacementChannel(nsIURI* newURI,
   return NS_OK;
 }
 
-bool HttpBaseChannel::ShouldTaintReplacementChannelOrigin(nsIURI* aNewURI) {
+bool HttpBaseChannel::ShouldTaintReplacementChannelOrigin(
+    nsIChannel* aNewChannel, uint32_t aRedirectFlags) {
   if (LoadTaintedOriginFlag()) {
     return true;
   }
 
+  if (NS_IsInternalSameURIRedirect(this, aNewChannel, aRedirectFlags) ||
+      NS_IsHSTSUpgradeRedirect(this, aNewChannel, aRedirectFlags)) {
+    return false;
+  }
+
   nsIScriptSecurityManager* ssm = nsContentUtils::GetSecurityManager();
   if (!ssm) {
     return true;
   }
-  nsresult rv = ssm->CheckSameOriginURI(aNewURI, mURI, false, false);
+
+  nsCOMPtr<nsIURI> newURI;
+  NS_GetFinalChannelURI(aNewChannel, getter_AddRefs(newURI));
+  nsresult rv = ssm->CheckSameOriginURI(newURI, mURI, false, false);
   if (NS_SUCCEEDED(rv)) {
     return false;
   }
-  // If aNewURI <-> mURI are not same-origin we need to taint unless
+  // If newURI <-> mURI are not same-origin we need to taint unless
   // mURI <-> mOriginalURI/LoadingPrincipal are same origin.
 
   if (mLoadInfo->GetLoadingPrincipal()) {
diff --git a/netwerk/protocol/http/HttpBaseChannel.h b/netwerk/protocol/http/HttpBaseChannel.h
index fa20f920a052..9e97abe7e1c4 100644
--- a/netwerk/protocol/http/HttpBaseChannel.h
+++ b/netwerk/protocol/http/HttpBaseChannel.h
@@ -570,7 +570,8 @@ class HttpBaseChannel : public nsHashPropertyBag,
       nsIURI*, nsIChannel*, bool preserveMethod, uint32_t redirectFlags);
 
   // WHATWG Fetch Standard 4.4. HTTP-redirect fetch, step 10
-  virtual bool ShouldTaintReplacementChannelOrigin(nsIURI* aNewURI);
+  virtual bool ShouldTaintReplacementChannelOrigin(nsIChannel* aNewChannel,
+                                                   uint32_t aRedirectFlags);
 
   // bundle calling OMR observers and marking flag into one function
   inline void CallOnModifyRequestObservers() {
diff --git a/netwerk/protocol/http/TRRServiceChannel.h b/netwerk/protocol/http/TRRServiceChannel.h
index 3bec408bf8de..deee6fefb1af 100644
--- a/netwerk/protocol/http/TRRServiceChannel.h
+++ b/netwerk/protocol/http/TRRServiceChannel.h
@@ -142,7 +142,8 @@ class TRRServiceChannel : public HttpBaseChannel,
       nsIURI* aNewURI, nsIChannel* aNewChannel, bool aPreserveMethod,
       uint32_t aRedirectFlags) override;
   // Skip this check for TRRServiceChannel.
-  virtual bool ShouldTaintReplacementChannelOrigin(nsIURI* aNewURI) override {
+  virtual bool ShouldTaintReplacementChannelOrigin(
+      nsIChannel* aNewChannel, uint32_t aRedirectFlags) override {
     return false;
   }
   virtual bool SameOriginWithOriginalUri(nsIURI* aURI) override;
diff --git a/netwerk/test/unit/test_httpssvc_https_upgrade.js b/netwerk/test/unit/test_httpssvc_https_upgrade.js
index 7e9e699a28e0..f49a56cb378e 100644
--- a/netwerk/test/unit/test_httpssvc_https_upgrade.js
+++ b/netwerk/test/unit/test_httpssvc_https_upgrade.js
@@ -18,6 +18,12 @@ const { TestUtils } = ChromeUtils.importESModule(
   "resource://testing-common/TestUtils.sys.mjs"
 );
 
+const ReferrerInfo = Components.Constructor(
+  "@mozilla.org/referrer-info;1",
+  "nsIReferrerInfo",
+  "init"
+);
+
 add_setup(async function setup() {
   trr_test_setup();
 
@@ -307,3 +313,43 @@ add_task(async function testHttpRequestBlocked() {
   dnsRequestObserver.unregister();
   await new Promise(resolve => httpserv.stop(resolve));
 });
+
+function createPrincipal(url) {
+  return Services.scriptSecurityManager.createContentPrincipal(
+    Services.io.newURI(url),
+    {}
+  );
+}
+
+// Test if the Origin header stays the same after an internal HTTPS upgrade
+// caused by HTTPS RR.
+add_task(async function testHTTPSRRUpgradeWithOriginHeader() {
+  dns.clearCache(true);
+
+  const url = "http://test.httpssvc.com:80/origin_header";
+  const originURL = "http://example.com";
+  let chan = Services.io
+    .newChannelFromURIWithProxyFlags(
+      Services.io.newURI(url),
+      null,
+      Ci.nsIProtocolProxyService.RESOLVE_ALWAYS_TUNNEL,
+      null,
+      createPrincipal(originURL),
+      createPrincipal(url),
+      Ci.nsILoadInfo.SEC_ALLOW_CROSS_ORIGIN_SEC_CONTEXT_IS_NULL,
+      Ci.nsIContentPolicy.TYPE_DOCUMENT
+    )
+    .QueryInterface(Ci.nsIHttpChannel);
+  chan.referrerInfo = new ReferrerInfo(
+    Ci.nsIReferrerInfo.EMPTY,
+    true,
+    NetUtil.newURI(url)
+  );
+  chan.setRequestHeader("Origin", originURL, false);
+
+  let [req, buf] = await channelOpenPromise(chan);
+
+  req.QueryInterface(Ci.nsIHttpChannel);
+  Assert.equal(req.getResponseHeader("x-connection-http2"), "yes");
+  Assert.equal(buf, originURL);
+});
diff --git a/testing/xpcshell/moz-http2/moz-http2.js b/testing/xpcshell/moz-http2/moz-http2.js
index 5075dbab4005..ebc18294ce36 100644
--- a/testing/xpcshell/moz-http2/moz-http2.js
+++ b/testing/xpcshell/moz-http2/moz-http2.js
@@ -1851,6 +1851,14 @@ function handleRequest(req, res) {
     res.writeHead(200);
     res.end("");
     return;
+  } else if (u.pathname === "/origin_header") {
+    let originHeader = req.headers.origin;
+    res.setHeader("Content-Length", originHeader.length);
+    res.setHeader("Content-Type", "text/plain");
+    res.writeHead(200);
+    res.write(originHeader);
+    res.end();
+    return;
   }
 
   res.setHeader("Content-Type", "text/html");
diff --git a/toolkit/components/extensions/test/xpcshell/test_ext_dnr_without_webrequest.js b/toolkit/components/extensions/test/xpcshell/test_ext_dnr_without_webrequest.js
index ed88b516c0bc..f7bea03a3b36 100644
--- a/toolkit/components/extensions/test/xpcshell/test_ext_dnr_without_webrequest.js
+++ b/toolkit/components/extensions/test/xpcshell/test_ext_dnr_without_webrequest.js
@@ -257,10 +257,8 @@ add_task(async function upgradeScheme_declarativeNetRequestWithHostAccess() {
   // https://github.com/w3c/webappsec-upgrade-insecure-requests/issues/32
   Assert.equal(
     (await contentFetch("http://dummy/", "http://redir/never_reached")).url,
-    // TODO bug 1800990: despite the mirrored Origin in ACAO, the CORS check
-    // fails after a request is upgraded. Once fixed, update this expectation:
-    undefined, // Should be: "http://dummy/cors_202?from_https",
-    "TODO 1800990: upgradeScheme + host access should upgrade (cross-origin request)"
+    "http://dummy/cors_202?from_https",
+    "upgradeScheme + host access should upgrade (cross-origin request)"
   );
 
   // The DNR extension does not have example.net in host_permissions.