diff --git a/src/input/plugins/CurlInputPlugin.cxx b/src/input/plugins/CurlInputPlugin.cxx
index 5cc29a539..7547b97f4 100644
--- a/src/input/plugins/CurlInputPlugin.cxx
+++ b/src/input/plugins/CurlInputPlugin.cxx
@@ -266,6 +266,7 @@ CurlInputStream::OnData(ConstBuffer<void> data)
 void
 CurlInputStream::OnEnd()
 {
+	const std::lock_guard<Mutex> protect(mutex);
 	cond.broadcast();
 
 	AsyncInputStream::SetClosed();
@@ -274,6 +275,7 @@ CurlInputStream::OnEnd()
 void
 CurlInputStream::OnError(std::exception_ptr e)
 {
+	const std::lock_guard<Mutex> protect(mutex);
 	postponed_exception = std::move(e);
 
 	if (IsSeekPending())