Chrome · Media
CVE-2026-110172
UAF in Media
Overview
High
Severity
—
CVSS
No
Exploited ITW
Fixed
Fix Status
Changed Functions
| Function | Change | Notes |
|---|---|---|
TEST_Fthird_party/blink/renderer/core/exported/web_media_player_impl_unittest.cc |
modified |
Files Changed
third_party/blink/renderer/core/exported/web_media_player_impl_unittest.ccthird_party/blink/renderer/platform/media/web_media_player_impl.cc
Patch
From 839f33256e792606993c2fae501babe68cd31921 Mon Sep 17 00:00:00 2001 From: Dale Curtis <[email protected]> Date: Thu, 08 Oct 2026 13:57:55 -0700 Subject: [PATCH] Cancel have_enough_after_lazy_load_cb_ in WebMediaPlayerImpl::Shutdown() When a lazy-loaded video suspends during startup, OnPipelineSuspended() posts have_enough_after_lazy_load_cb_ with a 250ms delay using base::Unretained(demuxer_manager_.get()). Previously, WebMediaPlayerImpl::Shutdown() moved demuxer_manager_ to DestructionHelper without cancelling have_enough_after_lazy_load_cb_. Because ~WebMediaPlayerImpl() is posted asynchronously via DeleteSoon, if demuxer_manager_ is destroyed and the 250ms delayed task runs before ~WebMediaPlayerImpl(), DemuxerManager::StopPreloading() is invoked on a freed DemuxerManager. Cancel have_enough_after_lazy_load_cb_ in WebMediaPlayerImpl::Shutdown() before transferring ownership of demuxer_manager_ to DestructionHelper. Fixed: 568719352 Change-Id: Ia70f3549f38985bfd7bdb57d33ebe3ac6d6664ec Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/8542870 Commit-Queue: Dale Curtis <[email protected]> Auto-Submit: Dale Curtis <[email protected]> Reviewed-by: Thomas Guilbert <[email protected]> Commit-Queue: Thomas Guilbert <[email protected]> Cr-Commit-Position: refs/heads/main@{#1714912} --- diff --git a/third_party/blink/renderer/platform/media/web_media_player_impl.cc b/third_party/blink/renderer/platform/media/web_media_player_impl.cc index 643e67a..f57bac24 100644 --- a/third_party/blink/renderer/platform/media/web_media_player_impl.cc +++ b/third_party/blink/renderer/platform/media/web_media_player_impl.cc @@ -699,6 +699,7 @@ simple_watch_timer_.Stop(); memory_usage_reporting_timer_.Stop(); update_background_status_cb_.Cancel(); + have_enough_after_lazy_load_cb_.Cancel(); media_log_->OnWebMediaPlayerDestroyed(); demuxer_manager_->StopAndResetClient(); @@ -1940,9 +1941,9 @@ // connection, briefly (250ms chosen arbitrarily) delay signaling "have // enough" to the MultiBufferDataSource. // - // Unretained() is safe here since the base::CancelableOnceClosure will - // cancel upon destruction of this class and `demuxer_manager_` is - // gauranteeed to outlive us as a result of the DestructionHelper. + // Unretained() is safe here since `have_enough_after_lazy_load_cb_` is + // cancelled in Shutdown() before `demuxer_manager_` is destroyed via + // DestructionHelper. have_enough_after_lazy_load_cb_.Reset( BindOnce(&media::DemuxerManager::StopPreloading, Unretained(demuxer_manager_.get()))); diff --git a/third_party/blink/renderer/core/exported/web_media_player_impl_unittest.cc b/third_party/blink/renderer/core/exported/web_media_player_impl_unittest.cc index fa28b63..7f24df0 100644 --- a/third_party/blink/renderer/core/exported/web_media_player_impl_unittest.cc +++ b/third_party/blink/renderer/core/exported/web_media_player_impl_unittest.cc @@ -1282,6 +1282,45 @@ EXPECT_CALL(*surface_layer_bridge_ptr_, ClearObserver()); } +// Verify that shutting down WebMediaPlayerImpl before destroying it cancels the +// delayed lazy load StopPreloading callback before DemuxerManager is destroyed. +TEST_F(WebMediaPlayerImplTest, + LazyLoadPreloadMetadataSuspendShutdownBeforeDestroy) { + InitializeWebMediaPlayerImpl(); + EXPECT_CALL(*client_, CouldPlayIfEnoughData()).WillRepeatedly(Return(false)); + wmpi_->SetPreload(WebMediaPlayer::kPreloadMetaData); + + LoadAndWaitForReadyState(kVideoOnlyTestFile, + WebMediaPlayer::kReadyStateHaveMetadata); + testing::Mock::VerifyAndClearExpectations(client_.Get()); + EXPECT_CALL(*client_, ReadyStateChanged()).Times(AnyNumber()); + CycleThreads(); + EXPECT_TRUE(IsSuspended()); + EXPECT_TRUE(wmpi_->DidLazyLoad()); + EXPECT_FALSE(ShouldCancelUponDefer()); + + EXPECT_CALL(*surface_layer_bridge_ptr_, ClearObserver()); + EXPECT_CALL(*client_, SetCcLayer(nullptr)); + EXPECT_CALL(*client_, MediaRemotingStopped(_)); + + // Shut down the player without destroying it yet, then cycle threads so + // DestructionHelper deletes `demuxer_manager_`. + wmpi_->Shutdown(); + CycleThreads(); + + // Wait past the 250ms delay used by `have_enough_after_lazy_load_cb_` while + // `wmpi_` is still alive. + base::RunLoop loop; + GetWebLocalFrame() + ->Scheduler() + ->GetTaskRunner(TaskType::kMediaElementEvent) + ->PostDelayedTask(FROM_HERE, loop.QuitClosure(), base::Milliseconds(300)); + loop.Run(); + + wmpi_.reset(); + CycleThreads(); +} + // Verify that lazy load is skipped when rVFC has been requested. TEST_F(WebMediaPlayerImplTest, LazyLoadSkippedForRVFC) { InitializeWebMediaPlayerImpl();
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Regression Test / PoC
shipped with the fix
diff --git a/third_party/blink/renderer/core/exported/web_media_player_impl_unittest.cc b/third_party/blink/renderer/core/exported/web_media_player_impl_unittest.cc
index fa28b63..7f24df0 100644
--- a/third_party/blink/renderer/core/exported/web_media_player_impl_unittest.cc
+++ b/third_party/blink/renderer/core/exported/web_media_player_impl_unittest.cc
@@ -1282,6 +1282,45 @@
EXPECT_CALL(*surface_layer_bridge_ptr_, ClearObserver());
}
+// Verify that shutting down WebMediaPlayerImpl before destroying it cancels the
+// delayed lazy load StopPreloading callback before DemuxerManager is destroyed.
+TEST_F(WebMediaPlayerImplTest,
+ LazyLoadPreloadMetadataSuspendShutdownBeforeDestroy) {
+ InitializeWebMediaPlayerImpl();
+ EXPECT_CALL(*client_, CouldPlayIfEnoughData()).WillRepeatedly(Return(false));
+ wmpi_->SetPreload(WebMediaPlayer::kPreloadMetaData);
+
+ LoadAndWaitForReadyState(kVideoOnlyTestFile,
+ WebMediaPlayer::kReadyStateHaveMetadata);
+ testing::Mock::VerifyAndClearExpectations(client_.Get());
+ EXPECT_CALL(*client_, ReadyStateChanged()).Times(AnyNumber());
+ CycleThreads();
+ EXPECT_TRUE(IsSuspended());
+ EXPECT_TRUE(wmpi_->DidLazyLoad());
+ EXPECT_FALSE(ShouldCancelUponDefer());
+
+ EXPECT_CALL(*surface_layer_bridge_ptr_, ClearObserver());
+ EXPECT_CALL(*client_, SetCcLayer(nullptr));
+ EXPECT_CALL(*client_, MediaRemotingStopped(_));
+
+ // Shut down the player without destroying it yet, then cycle threads so
+ // DestructionHelper deletes `demuxer_manager_`.
+ wmpi_->Shutdown();
+ CycleThreads();
+
+ // Wait past the 250ms delay used by `have_enough_after_lazy_load_cb_` while
+ // `wmpi_` is still alive.
+ base::RunLoop loop;
+ GetWebLocalFrame()
+ ->Scheduler()
+ ->GetTaskRunner(TaskType::kMediaElementEvent)
+ ->PostDelayedTask(FROM_HERE, loop.QuitClosure(), base::Milliseconds(300));
+ loop.Run();
+
+ wmpi_.reset();
+ CycleThreads();
+}
+
// Verify that lazy load is skipped when rVFC has been requested.
TEST_F(WebMediaPlayerImplTest, LazyLoadSkippedForRVFC) {
InitializeWebMediaPlayerImpl();
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Original Bug Report
The reporter's bug is still restricted on the tracker. Chrome de-restricts security bugs ~30–90 days after the fix ships; a later run will backfill it here.
References
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