diff --git chrome/browser/plugins/plugin_info_host_impl.cc chrome/browser/plugins/plugin_info_host_impl.cc
index 2bb525046619c..200fc9c1f0067 100644
--- chrome/browser/plugins/plugin_info_host_impl.cc
+++ chrome/browser/plugins/plugin_info_host_impl.cc
@@ -16,6 +16,7 @@
 #include "base/memory/singleton.h"
 #include "build/branding_buildflags.h"
 #include "build/build_config.h"
+#include "cef/libcef/features/features.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/content_settings/host_content_settings_map_factory.h"
 #include "chrome/browser/plugins/chrome_plugin_service_filter.h"
@@ -140,6 +141,12 @@ bool IsPluginLoadingAccessibleResourceInWebView(
     extensions::ExtensionRegistry* extension_registry,
     int process_id,
     const GURL& resource) {
+#if BUILDFLAG(ENABLE_ALLOY_BOOTSTRAP)
+  // May be nullptr if using CEF Alloy with extensions disabled.
+  if (!extension_registry)
+    return false;
+#endif
+
   extensions::WebViewRendererState* renderer_state =
       extensions::WebViewRendererState::GetInstance();
   std::string partition_id;
diff --git chrome/browser/plugins/plugin_utils.cc chrome/browser/plugins/plugin_utils.cc
index 438276b719c2f..e97fa0eaf2d7a 100644
--- chrome/browser/plugins/plugin_utils.cc
+++ chrome/browser/plugins/plugin_utils.cc
@@ -5,6 +5,7 @@
 #include "chrome/browser/plugins/plugin_utils.h"
 
 #include "base/values.h"
+#include "cef/libcef/features/features.h"
 #include "chrome/browser/profiles/profile.h"
 #include "components/content_settings/core/browser/host_content_settings_map.h"
 #include "components/content_settings/core/common/content_settings_types.h"
@@ -68,6 +69,15 @@ PluginUtils::GetMimeTypeToExtensionIdMap(
     content::BrowserContext* browser_context) {
   base::flat_map<std::string, std::string> mime_type_to_extension_id_map;
 #if BUILDFLAG(ENABLE_EXTENSIONS)
+#if BUILDFLAG(ENABLE_ALLOY_BOOTSTRAP)
+  // May be nullptr if using CEF Alloy with extensions disabled.
+  extensions::ExtensionRegistry* registry =
+      extensions::ExtensionRegistry::Get(browser_context);
+  if (!registry) {
+    return mime_type_to_extension_id_map;
+  }
+#endif
+
   Profile* profile = Profile::FromBrowserContext(browser_context);
   if (extensions::ChromeContentBrowserClientExtensionsPart::
           AreExtensionsDisabledForProfile(profile)) {
@@ -78,9 +88,11 @@ PluginUtils::GetMimeTypeToExtensionIdMap(
       MimeTypesHandler::GetMIMETypeAllowlist();
   // Go through the allowed extensions and try to use them to intercept
   // the URL request.
+#if !BUILDFLAG(ENABLE_ALLOY_BOOTSTRAP)
   extensions::ExtensionRegistry* registry =
       extensions::ExtensionRegistry::Get(browser_context);
   DCHECK(registry);
+#endif
   for (const std::string& extension_id : allowlist) {
     const extensions::Extension* extension =
         registry->enabled_extensions().GetByID(extension_id);
diff --git chrome/renderer/chrome_content_renderer_client.cc chrome/renderer/chrome_content_renderer_client.cc
index 620f0ebad27d3..f36f4a6c5d1ee 100644
--- chrome/renderer/chrome_content_renderer_client.cc
+++ chrome/renderer/chrome_content_renderer_client.cc
@@ -1007,6 +1007,7 @@ WebPlugin* ChromeContentRendererClient::CreatePlugin(
 
     if ((status == chrome::mojom::PluginStatus::kUnauthorized ||
          status == chrome::mojom::PluginStatus::kBlocked) &&
+        content_settings_agent_delegate &&
         content_settings_agent_delegate->IsPluginTemporarilyAllowed(
             identifier)) {
       status = chrome::mojom::PluginStatus::kAllowed;
@@ -1167,7 +1168,8 @@ WebPlugin* ChromeContentRendererClient::CreatePlugin(
         render_frame->GetRemoteAssociatedInterfaces()->GetInterface(
             plugin_auth_host.BindNewEndpointAndPassReceiver());
         plugin_auth_host->BlockedUnauthorizedPlugin(group_name, identifier);
-        content_settings_agent->DidBlockContentType(content_type);
+        if (content_settings_agent)
+          content_settings_agent->DidBlockContentType(content_type);
         break;
       }
       case chrome::mojom::PluginStatus::kBlocked: {
@@ -1176,7 +1178,8 @@ WebPlugin* ChromeContentRendererClient::CreatePlugin(
             l10n_util::GetStringFUTF16(IDS_PLUGIN_BLOCKED, group_name));
         placeholder->AllowLoading();
         RenderThread::Get()->RecordAction(UserMetricsAction("Plugin_Blocked"));
-        content_settings_agent->DidBlockContentType(content_type);
+        if (content_settings_agent)
+          content_settings_agent->DidBlockContentType(content_type);
         break;
       }
       case chrome::mojom::PluginStatus::kBlockedByPolicy: {
@@ -1186,7 +1189,8 @@ WebPlugin* ChromeContentRendererClient::CreatePlugin(
                                        group_name));
         RenderThread::Get()->RecordAction(
             UserMetricsAction("Plugin_BlockedByPolicy"));
-        content_settings_agent->DidBlockContentType(content_type);
+        if (content_settings_agent)
+          content_settings_agent->DidBlockContentType(content_type);
         break;
       }
     }
diff --git content/browser/browser_plugin/browser_plugin_embedder.h content/browser/browser_plugin/browser_plugin_embedder.h
index 8b26a93f7527e..17890bf20e481 100644
--- content/browser/browser_plugin/browser_plugin_embedder.h
+++ content/browser/browser_plugin/browser_plugin_embedder.h
@@ -15,6 +15,7 @@
 #define CONTENT_BROWSER_BROWSER_PLUGIN_BROWSER_PLUGIN_EMBEDDER_H_
 
 #include "base/memory/raw_ptr.h"
+#include "content/common/content_export.h"
 
 namespace content {
 
@@ -26,7 +27,7 @@ struct NativeWebKeyboardEvent;
 
 // TODO(wjmaclean): Get rid of "BrowserPlugin" in the name of this class.
 // Perhaps "WebContentsEmbedderDelegate" would be better?
-class BrowserPluginEmbedder {
+class CONTENT_EXPORT BrowserPluginEmbedder {
  public:
   BrowserPluginEmbedder(const BrowserPluginEmbedder&) = delete;
   BrowserPluginEmbedder& operator=(const BrowserPluginEmbedder&) = delete;
diff --git content/browser/browser_plugin/browser_plugin_guest.cc content/browser/browser_plugin/browser_plugin_guest.cc
index f94fcfcf562db..066c66f46b7ae 100644
--- content/browser/browser_plugin/browser_plugin_guest.cc
+++ content/browser/browser_plugin/browser_plugin_guest.cc
@@ -49,6 +49,8 @@ std::unique_ptr<WebContentsImpl> BrowserPluginGuest::CreateNewGuestWindow(
 }
 
 void BrowserPluginGuest::InitInternal(WebContentsImpl* owner_web_contents) {
+  owner_web_contents_ = owner_web_contents;
+
   RenderWidgetHostImpl* rwhi =
       GetWebContents()->GetPrimaryMainFrame()->GetRenderWidgetHost();
   DCHECK(rwhi);
diff --git content/browser/browser_plugin/browser_plugin_guest.h content/browser/browser_plugin/browser_plugin_guest.h
index 7f3083029d45e..94a5cbed96a10 100644
--- content/browser/browser_plugin/browser_plugin_guest.h
+++ content/browser/browser_plugin/browser_plugin_guest.h
@@ -70,6 +70,8 @@ class BrowserPluginGuest : public WebContentsObserver {
   WebContentsImpl* GetWebContents() const;
   RenderFrameHostImpl* GetProspectiveOuterDocument();
 
+  WebContentsImpl* owner_web_contents() const { return owner_web_contents_; }
+
  private:
   // BrowserPluginGuest is a WebContentsObserver of |web_contents| and
   // |web_contents| has to stay valid for the lifetime of BrowserPluginGuest.
@@ -80,6 +82,8 @@ class BrowserPluginGuest : public WebContentsObserver {
 
   // May be null during guest destruction.
   const base::WeakPtr<BrowserPluginGuestDelegate> delegate_;
+
+  raw_ptr<WebContentsImpl> owner_web_contents_ = nullptr;
 };
 
 }  // namespace content