diff --git a/components/password_manager/core/browser/password_manual_fallback_flow.cc b/components/password_manager/core/browser/password_manual_fallback_flow.cc
index 8e847531b32e9..cc0dbd9a0c3bc 100644
--- a/components/password_manager/core/browser/password_manual_fallback_flow.cc
+++ b/components/password_manager/core/browser/password_manual_fallback_flow.cc
@@ -266,6 +266,12 @@ void PasswordManualFallbackFlow::DidAcceptSuggestion(
       "PasswordManager.ManualFallback.AcceptedSuggestion.FromRootPopup",
       metadata.sub_popup_level == 0);
 
+  // On macOS without biometrics, the kPasswordEntry / kFillPassword /
+  // kViewPasswordDetails branches below can synchronously enter
+  // AuthorizationCopyRights, which pumps a nested CFRunLoop on the UI thread.
+  // The page (and therefore `this`) can be torn down inside that loop, so
+  // guard the trailing `autofill_client_` dereference.
+  auto weak_this = weak_ptr_factory_.GetWeakPtr();
   switch (suggestion.type) {
     case autofill::SuggestionType::kPasswordEntry: {
       if (!form) {
@@ -339,6 +345,9 @@ void PasswordManualFallbackFlow::DidAcceptSuggestion(
       // Other suggestion types are not supported.
       NOTREACHED();
   }
+  if (!weak_this) {
+    return;
+  }
   autofill_client_->HideAutofillSuggestions(
       autofill::SuggestionHidingReason::kAcceptSuggestion);
 }