diff --git a/third_party/blink/renderer/core/inspector/network_resources_data.cc b/third_party/blink/renderer/core/inspector/network_resources_data.cc
index 694d430c47be3..c184bed01d218 100644
--- a/third_party/blink/renderer/core/inspector/network_resources_data.cc
+++ b/third_party/blink/renderer/core/inspector/network_resources_data.cc
@@ -474,6 +474,13 @@ bool NetworkResourcesData::EnsureFreeSpace(uint64_t size) {
     return false;
 
   while (content_size_ + size > maximum_resources_content_size_) {
+    if (request_ids_deque_.empty()) {
+      // `content_size_` can be desynced from `request_ids_deque_` after
+      // `Clear(preserved_loader_id)` re-adds preserved bytes without
+      // re-queuing their request ids. Bail out instead of popping an empty
+      // (capacity-0, nullptr-backed) deque.
+      return false;
+    }
     String request_id = request_ids_deque_.TakeFirst();
     ResourceData* resource_data = ResourceDataForRequestId(request_id);
     if (resource_data)