--- a/third_party/blink/renderer/modules/indexeddb/inspector_indexed_db_agent.h
+++ b/third_party/blink/renderer/modules/indexeddb/inspector_indexed_db_agent.h
@@ -57,6 +57,7 @@
 
   v8_inspector::V8InspectorSession* v8_session() { return v8_session_; }
 
+  void Dispose() override;
   void Restore() override;
   void DidCommitLoadForLocalFrame(LocalFrame*) override;
 
@@ -115,6 +116,8 @@
       std::unique_ptr<DeleteDatabaseCallback>) override;
 
  private:
+  void ReleaseObjectGroup();
+
   // This is null while inspecting workers.
   Member<InspectedFrames> inspected_frames_;
   // This is null while inspecting frames.
--- a/third_party/blink/renderer/modules/indexeddb/inspector_indexed_db_agent.cc
+++ b/third_party/blink/renderer/modules/indexeddb/inspector_indexed_db_agent.cc
@@ -104,6 +104,8 @@
 
 const char kIndexedDBObjectGroup[] = "indexeddb";
 const char kNoDocumentError[] = "No document for given frame found";
+const char kSessionDetachedDuringOperation[] =
+    "DevTools session detached during operation.";
 const char kOriginMismatchError[] =
     "Requested security origin does not match the target's origin.";
 
@@ -678,18 +680,29 @@
     result_ = std::make_unique<protocol::Array<DataEntry>>();
   }
   ~OpenCursorCallback() override = default;
+
+  void SendFailure(protocol::Response response) {
+    if (!request_callback_) {
+      return;
+    }
+    auto request_callback = std::move(request_callback_);
+    request_callback->sendFailure(std::move(response));
+  }
 
   void Invoke(ExecutionContext*, Event* event) override {
+    if (!request_callback_) {
+      return;
+    }
+
     InspectorIndexedDBAgent* agent = agent_.Get();
     if (!agent) {
-      request_callback_->sendFailure(protocol::Response::ServerError(
-          "DevTools session detached during operation."));
+      SendFailure(
+          protocol::Response::ServerError(kSessionDetachedDuringOperation));
       return;
     }
 
     if (event->type() != event_type_names::kSuccess) {
-      request_callback_->sendFailure(
-          protocol::Response::ServerError("Unexpected event type."));
+      SendFailure(protocol::Response::ServerError("Unexpected event type."));
       return;
     }
 
@@ -700,8 +713,7 @@
       return;
     }
     if (request_result->GetType() != IDBAny::kIDBCursorWithValueType) {
-      request_callback_->sendFailure(
-          protocol::Response::ServerError("Unexpected result type."));
+      SendFailure(protocol::Response::ServerError("Unexpected result type."));
       return;
     }
 
@@ -711,8 +723,7 @@
       DummyExceptionStateForTesting exception_state;
       idb_cursor->advance(skip_count_, exception_state);
       if (exception_state.HadException()) {
-        request_callback_->sendFailure(
-            protocol::Response::ServerError("Could not advance cursor."));
+        SendFailure(protocol::Response::ServerError("Could not advance cursor."));
       }
       skip_count_ = 0;
       return;
@@ -729,8 +740,7 @@
     idb_cursor->Continue(nullptr, nullptr, IDBRequest::AsyncTraceState(),
                          exception_state);
     if (exception_state.HadException()) {
-      request_callback_->sendFailure(
-          protocol::Response::ServerError("Could not continue cursor."));
+      SendFailure(protocol::Response::ServerError("Could not continue cursor."));
       return;
     }
 
@@ -739,6 +749,11 @@
     }
 
     v8_inspector::V8InspectorSession* v8_session = agent->v8_session();
+    if (!v8_session) {
+      SendFailure(
+          protocol::Response::ServerError(kSessionDetachedDuringOperation));
+      return;
+    }
     ScriptState::Scope scope(script_state_);
     v8::Local<v8::Context> context = script_state_->GetContext();
     v8_inspector::StringView object_group =
@@ -759,7 +774,11 @@
   }
 
   void end(bool has_more) {
-    request_callback_->sendSuccess(std::move(result_), has_more);
+    if (!request_callback_) {
+      return;
+    }
+    auto request_callback = std::move(request_callback_);
+    request_callback->sendSuccess(std::move(result_), has_more);
   }
 
   void Trace(Visitor* visitor) const override {
@@ -796,10 +815,9 @@
 
   void Execute(IDBDatabase* idb_database, ScriptState* script_state) override {
     InspectorIndexedDBAgent* agent = agent_.Get();
-    if (!agent) {
-      request_callback_->sendFailure(protocol::Response::ServerError(
-          "The DevTools session was detached before the operation could "
-          "complete."));
+    if (!agent || !agent->v8_session()) {
+      request_callback_->sendFailure(
+          protocol::Response::ServerError(kSessionDetachedDuringOperation));
       return;
     }
 
@@ -883,6 +901,22 @@
 
 InspectorIndexedDBAgent::~InspectorIndexedDBAgent() = default;
 
+void InspectorIndexedDBAgent::Dispose() {
+  ReleaseObjectGroup();
+  // Make any outstanding asynchronous IndexedDB callbacks fail closed before
+  // DevToolsSession tears down the underlying V8InspectorSession.
+  v8_session_ = nullptr;
+  InspectorBaseAgent<protocol::IndexedDB::Metainfo>::Dispose();
+}
+
+void InspectorIndexedDBAgent::ReleaseObjectGroup() {
+  if (!v8_session_) {
+    return;
+  }
+  v8_session_->releaseObjectGroup(
+      ToV8InspectorStringView(kIndexedDBObjectGroup));
+}
+
 void InspectorIndexedDBAgent::Restore() {
   if (enabled_.Get()) {
     enable();
@@ -891,8 +925,7 @@
 
 void InspectorIndexedDBAgent::DidCommitLoadForLocalFrame(LocalFrame* frame) {
   if (frame == inspected_frames_->Root()) {
-    v8_session_->releaseObjectGroup(
-        ToV8InspectorStringView(kIndexedDBObjectGroup));
+    ReleaseObjectGroup();
   }
 }
 
@@ -903,8 +936,7 @@
 
 protocol::Response InspectorIndexedDBAgent::disable() {
   enabled_.Clear();
-  v8_session_->releaseObjectGroup(
-      ToV8InspectorStringView(kIndexedDBObjectGroup));
+  ReleaseObjectGroup();
   return protocol::Response::Success();
 }