diff --git a/netwerk/protocol/http/TunnelUtils.cpp b/netwerk/protocol/http/TunnelUtils.cpp
index d0f6ef0b1873..0cf3ea4f3008 100644
--- a/netwerk/protocol/http/TunnelUtils.cpp
+++ b/netwerk/protocol/http/TunnelUtils.cpp
@@ -126,6 +126,10 @@ TLSFilterTransaction::Close(nsresult aReason)
     return;
   }
 
+  if (mTimer) {
+    mTimer->Cancel();
+    mTimer = nullptr;
+  }
   mTransaction->Close(aReason);
   mTransaction = nullptr;
 }