diff --git a/buffer.c b/buffer.c
index 5cbd10b1..3bec0c63 100644
--- a/buffer.c
+++ b/buffer.c
@@ -1969,7 +1969,7 @@ evbuffer_write_atmost(struct evbuffer *buffer, evutil_socket_t fd,
 		goto done;
 	}
 
-	if (howmuch < 0)
+	if (howmuch < 0 || howmuch > buffer->total_len)
 		howmuch = buffer->total_len;
 
 	{