diff --git a/src/g_shared/shared_sbar.cpp b/src/g_shared/shared_sbar.cpp
index 7f55fe0d0f..d2636d337d 100644
--- a/src/g_shared/shared_sbar.cpp
+++ b/src/g_shared/shared_sbar.cpp
@@ -391,6 +391,12 @@ void DBaseStatusBar::AttachMessage (DHUDMessage *msg, DWORD id, int layer)
 		old->Destroy();
 	}
 
+	// Merge unknown layers into the default layer.
+	if ((size_t)layer >= countof(Messages))
+	{
+		layer = HUDMSGLayer_Default;
+	}
+
 	prev = &Messages[layer];
 
 	// The ID serves as a priority, where lower numbers appear in front of