diff --git a/zircon/system/ulib/audio-utils/audio-device-stream.cpp b/zircon/system/ulib/audio-utils/audio-device-stream.cpp
index d2ac4db3..4ee168e 100644
--- a/zircon/system/ulib/audio-utils/audio-device-stream.cpp
+++ b/zircon/system/ulib/audio-utils/audio-device-stream.cpp
@@ -98,7 +98,7 @@
 
 AudioDeviceStream::AudioDeviceStream(bool input, const char* dev_path)
     : input_(input) {
-    strncpy(name_, dev_path, sizeof(name_));
+    strncpy(name_, dev_path, sizeof(name_) - 1);
     name_[sizeof(name_) - 1] = 0;
 }