diff --git a/extensions/browser/api/user_scripts/user_scripts_api.cc b/extensions/browser/api/user_scripts/user_scripts_api.cc
index c5f00b8940e915..46ef2c00622177 100644
--- a/extensions/browser/api/user_scripts/user_scripts_api.cc
+++ b/extensions/browser/api/user_scripts/user_scripts_api.cc
@@ -695,18 +695,8 @@ ExtensionFunction::ResponseAction UserScriptsExecuteFunction::Run() {
   }
 
   // Validate injection target.
-  scripting::InjectionTarget internal_injection_target =
+  injection_target_ =
       ConvertToInternalInjectionTarget(std::move(injection_.target));
-  ScriptExecutor* script_executor = nullptr;
-  ScriptExecutor::FrameScope frame_scope = ScriptExecutor::SPECIFIED_FRAMES;
-  std::set<int> frame_ids;
-  if (!scripting::CanAccessTarget(
-          *extension()->permissions_data(), internal_injection_target,
-          browser_context(), include_incognito_information(), &script_executor,
-          &frame_scope, &frame_ids, &error)) {
-    return RespondNow(Error(std::move(error)));
-  }
-
   // Retrieve injection sources in order. Since file sources need to be loaded,
   // we use a nullopt for placeholder in the source list. After files are
   // successfully loaded, they should be converted to js source too.
@@ -729,21 +719,18 @@ ExtensionFunction::ResponseAction UserScriptsExecuteFunction::Run() {
         std::move(file_sources), script_parsing::ContentScriptType::kJs,
         *extension(), kRequiresLocalization,
         base::BindOnce(&UserScriptsExecuteFunction::DidLoadResources, this,
-                       script_executor, frame_scope, std::move(frame_ids),
                        std::move(sources)),
         &error);
-  } else {
-    Execute(std::move(sources), script_executor, frame_scope, frame_ids,
-            &error);
+    return RespondLater();
   }
 
+  if (!Execute(std::move(sources), &error)) {
+    return RespondNow(Error(std::move(error)));
+  }
   return RespondLater();
 }
 
 void UserScriptsExecuteFunction::DidLoadResources(
-    ScriptExecutor* script_executor,
-    ScriptExecutor::FrameScope frame_scope,
-    std::set<int> frame_ids,
     std::vector<std::optional<mojom::JSSourcePtr>> sources,
     std::vector<scripting::InjectedFileSource> file_sources,
     std::optional<std::string> load_error) {
@@ -773,15 +760,30 @@ void UserScriptsExecuteFunction::DidLoadResources(
   CHECK_EQ(file_index, static_cast<int>(file_sources.size()));
 
   std::string error;
-  Execute(std::move(sources), script_executor, frame_scope, frame_ids, &error);
+  if (!Execute(std::move(sources), &error)) {
+    Respond(Error(std::move(error)));
+  }
 }
 
-void UserScriptsExecuteFunction::Execute(
+bool UserScriptsExecuteFunction::Execute(
     std::vector<std::optional<mojom::JSSourcePtr>> sources,
-    ScriptExecutor* script_executor,
-    ScriptExecutor::FrameScope frame_scope,
-    std::set<int> frame_ids,
     std::string* error) {
+  // Resolve and validate the injection target now (mirroring
+  // ScriptingExecuteScriptFunction::Execute()), so that the per-frame
+  // permission check observes the same RenderFrameHosts that
+  // ScriptExecutor::Handler will resolve and pass to
+  // ScriptInjectionTracker::WillExecuteCode() — not stale ones captured
+  // before the asynchronous file load in Run().
+  ScriptExecutor* script_executor = nullptr;
+  ScriptExecutor::FrameScope frame_scope = ScriptExecutor::SPECIFIED_FRAMES;
+  std::set<int> frame_ids;
+  if (!scripting::CanAccessTarget(
+          *extension()->permissions_data(), injection_target_,
+          browser_context(), include_incognito_information(), &script_executor,
+          &frame_scope, &frame_ids, error)) {
+    return false;
+  }
+
   mojom::ExecutionWorld execution_world =
       ConvertExecutionWorld(injection_.world);
   std::optional<std::string> execution_world_id = injection_.world_id;
@@ -799,6 +801,7 @@ void UserScriptsExecuteFunction::Execute(
       execution_world_id, script_executor, frame_scope, frame_ids,
       inject_immediately, user_gesture(),
       base::BindOnce(&UserScriptsExecuteFunction::OnScriptExecuted, this));
+  return true;
 }
 
 void UserScriptsExecuteFunction::OnScriptExecuted(
diff --git a/extensions/browser/api/user_scripts/user_scripts_api.h b/extensions/browser/api/user_scripts/user_scripts_api.h
index 0d77d7ec416e9d..63dfa0defa626c 100644
--- a/extensions/browser/api/user_scripts/user_scripts_api.h
+++ b/extensions/browser/api/user_scripts/user_scripts_api.h
@@ -115,24 +115,21 @@ class UserScriptsExecuteFunction : public ExtensionFunction {
   ~UserScriptsExecuteFunction() override = default;
 
   // Called when the resource files to be injected has been loaded.
-  void DidLoadResources(ScriptExecutor* script_executor,
-                        ScriptExecutor::FrameScope frame_scope,
-                        std::set<int> frame_ids,
-                        std::vector<std::optional<mojom::JSSourcePtr>> sources,
+  void DidLoadResources(std::vector<std::optional<mojom::JSSourcePtr>> sources,
                         std::vector<scripting::InjectedFileSource> file_sources,
                         std::optional<std::string> load_error);
 
-  // Triggers the execution of `sources` in the appropriate context.
-  void Execute(std::vector<std::optional<mojom::JSSourcePtr>> sources,
-               ScriptExecutor* script_executor,
-               ScriptExecutor::FrameScope frame_scope,
-               std::set<int> frame_ids,
+  // Triggers the execution of `sources` in the appropriate context. Re-resolves
+  // and re-validates the injection target so that frame_ids captured before the
+  // async file load are not used after a cross-origin navigation.
+  bool Execute(std::vector<std::optional<mojom::JSSourcePtr>> sources,
                std::string* error);
 
   // Invoked when script execution is complete.
   void OnScriptExecuted(std::vector<ScriptExecutor::FrameResult> frame_results);
 
   api::user_scripts::UserScriptInjection injection_;
+  scripting::InjectionTarget injection_target_;
 };
 
 class UserScriptsConfigureWorldFunction : public ExtensionFunction {
diff --git a/extensions/browser/scripting_utils.cc b/extensions/browser/scripting_utils.cc
index cb04eba0c4553b..68ae3369792edc 100644
--- a/extensions/browser/scripting_utils.cc
+++ b/extensions/browser/scripting_utils.cc
@@ -182,6 +182,8 @@ InjectionTarget::InjectionTarget() : tab_id(-1) {}
 
 InjectionTarget::InjectionTarget(InjectionTarget&& other) = default;
 
+InjectionTarget& InjectionTarget::operator=(InjectionTarget&& other) = default;
+
 InjectionTarget::~InjectionTarget() = default;
 
 InjectedFileSource::InjectedFileSource(std::string file_name, std::string data)
diff --git a/extensions/browser/scripting_utils.h b/extensions/browser/scripting_utils.h
index 837c0c7b88ed85..52f02ccf1daf41 100644
--- a/extensions/browser/scripting_utils.h
+++ b/extensions/browser/scripting_utils.h
@@ -29,6 +29,7 @@ namespace extensions::scripting {
 struct InjectionTarget {
   InjectionTarget();
   InjectionTarget(InjectionTarget&& other);
+  InjectionTarget& operator=(InjectionTarget&& other);
   ~InjectionTarget();
 
   // Whether the script should inject into all frames within the tab.