--- a/media/webrtc/signaling/gtest/jsep_session_unittest.cpp
+++ b/media/webrtc/signaling/gtest/jsep_session_unittest.cpp
@@ -1425,16 +1425,52 @@ TEST_P(JsepSessionTest, DISABLED_Renegot
   }
 
   ASSERT_EQ(answererPairs.size(), newOffererPairs.size());
   for (size_t i = 0; i < answererPairs.size(); ++i) {
     ASSERT_TRUE(Equals(answererPairs[i], newOffererPairs[i]));
   }
 }
 
+// We don't want to offer to receive extensions that are send only.
+// This tests that we filter them out properly when we reoffer.
+// See Bug 1362581.
+TEST_F(JsepSessionTest, RenegotiationSwappedRolesCheckAudioLevelExt)
+{
+  AddTracks(*mSessionOff, "audio,video");
+  mSessionOff->AddAudioRtpExtension("urn:ietf:params:rtp-hdrext:ssrc-audio-level",
+                                    SdpDirectionAttribute::Direction::kSendonly);
+  std::string offer = CreateOffer();
+
+  SetLocalOffer(offer, CHECK_SUCCESS);
+  SetRemoteOffer(offer, CHECK_SUCCESS);
+
+  UniquePtr<Sdp> parsedOffer(Parse(offer));
+  auto& offerMediaAttrs = parsedOffer->GetMediaSection(0).GetAttributeList();
+  ASSERT_TRUE(offerMediaAttrs.HasAttribute(SdpAttribute::kExtmapAttribute));
+  auto& offerExtmap = offerMediaAttrs.GetExtmap().mExtmaps;
+  ASSERT_EQ(1U, offerExtmap.size());
+  ASSERT_EQ("urn:ietf:params:rtp-hdrext:ssrc-audio-level",
+      offerExtmap[0].extensionname);
+
+  std::string answer = CreateAnswer();
+  SetLocalAnswer(answer, CHECK_SUCCESS);
+  SetRemoteAnswer(answer, CHECK_SUCCESS);
+
+  UniquePtr<Sdp> parsedAnswer(Parse(answer));
+  auto& answerMediaAttrs = parsedAnswer->GetMediaSection(0).GetAttributeList();
+  ASSERT_FALSE(answerMediaAttrs.HasAttribute(SdpAttribute::kExtmapAttribute));
+
+  SwapOfferAnswerRoles();
+
+  std::string reoffer = CreateOffer();
+  UniquePtr<Sdp> parsedReoffer(Parse(reoffer));
+  auto& reofferMediaAttrs = parsedReoffer->GetMediaSection(0).GetAttributeList();
+  ASSERT_FALSE(reofferMediaAttrs.HasAttribute(SdpAttribute::kExtmapAttribute));
+}
 
 TEST_P(JsepSessionTest, RenegotiationOffererAddsTrack)
 {
   AddTracks(*mSessionOff);
   AddTracks(*mSessionAns);
 
   OfferAnswer();
 

--- a/media/webrtc/signaling/src/jsep/JsepSessionImpl.cpp
+++ b/media/webrtc/signaling/src/jsep/JsepSessionImpl.cpp
@@ -526,16 +526,30 @@ JsepSessionImpl::BindRemoteTracks(SdpMed
 
     if (!track.mAssignedMLine.isSome()) {
       MOZ_ASSERT(false);
       continue;
     }
 
     auto& msection = sdp->GetMediaSection(*track.mAssignedMLine);
 
+    // Filter out extensions that are send only so we don't offer to
+    // receive them.
+    auto& attrs = msection.GetAttributeList();
+    if (attrs.HasAttribute(SdpAttribute::kExtmapAttribute)) {
+      UniquePtr<SdpExtmapAttributeList> new_list(new SdpExtmapAttributeList);
+      for (auto& ext : attrs.GetExtmap().mExtmaps) {
+        if (ext.direction != SdpDirectionAttribute::kSendonly) {
+          new_list->mExtmaps.push_back(ext);
+        }
+      }
+      attrs.RemoveAttribute(SdpAttribute::kExtmapAttribute);
+      attrs.SetAttribute(new_list.release());
+    }
+
     if (mSdpHelper.MsectionIsDisabled(msection)) {
       // TODO(bug 1095226) Content probably disabled this? Should we allow
       // content to do this?
       continue;
     }
 
     track.mTrack->AddToOffer(&msection);