--- a/dom/media/mediasource/SourceBuffer.cpp
+++ b/dom/media/mediasource/SourceBuffer.cpp
@@ -187,16 +187,20 @@ SourceBuffer::Abort(ErrorResult& aRv)
   if (!IsAttached()) {
     aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
     return;
   }
   if (mMediaSource->ReadyState() != MediaSourceReadyState::Open) {
     aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
     return;
   }
+  if (mPendingRemoval.Exists()) {
+    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
+    return;
+  }
   AbortBufferAppend();
   ResetParserState();
   mCurrentAttributes.SetAppendWindowStart(0);
   mCurrentAttributes.SetAppendWindowEnd(PositiveInfinity<double>());
 }
 
 void
 SourceBuffer::AbortBufferAppend()
@@ -243,21 +247,25 @@ SourceBuffer::Remove(double aStart, doub
 }
 
 void
 SourceBuffer::RangeRemoval(double aStart, double aEnd)
 {
   StartUpdating();
 
   RefPtr<SourceBuffer> self = this;
-  mTrackBuffersManager->RangeRemoval(TimeUnit::FromSeconds(aStart),
-                                     TimeUnit::FromSeconds(aEnd))
-    ->Then(AbstractThread::MainThread(), __func__,
-           [self] (bool) { self->StopUpdating(); },
-           []() { MOZ_ASSERT(false); });
+  mPendingRemoval.Begin(
+    mTrackBuffersManager->RangeRemoval(TimeUnit::FromSeconds(aStart),
+                                       TimeUnit::FromSeconds(aEnd))
+      ->Then(AbstractThread::MainThread(), __func__,
+             [self] (bool) {
+               self->mPendingRemoval.Complete();
+               self->StopUpdating();
+             },
+             []() { MOZ_ASSERT(false); }));
 }
 
 void
 SourceBuffer::Detach()
 {
   MOZ_ASSERT(NS_IsMainThread());
   MSE_DEBUG("Detach");
   if (!mMediaSource) {

--- a/dom/media/mediasource/SourceBuffer.h
+++ b/dom/media/mediasource/SourceBuffer.h
@@ -169,16 +169,17 @@ private:
   RefPtr<TrackBuffersManager> mTrackBuffersManager;
   SourceBufferAttributes mCurrentAttributes;
 
   bool mUpdating;
 
   mozilla::Atomic<bool> mActive;
 
   MozPromiseRequestHolder<SourceBufferTask::AppendPromise> mPendingAppend;
+  MozPromiseRequestHolder<SourceBufferTask::RangeRemovalPromise> mPendingRemoval;
   const nsCString mType;
 
   RefPtr<TimeRanges> mBuffered;
 };
 
 } // namespace dom
 
 } // namespace mozilla