For a couple years, new services with low-latency requirements appear to be a major challenge for the future Internet. Many optimizations, all targeting the latency reduction have been proposed, and among them, re-architecting the network packet processing has been particularly considered. In this effort, the L4S proposal aims at allowing both classic and low-latency traffic to cohabit within a single node architecture. However, although this architecture sounds promising for latency improvement, it also lacks an in-depth study of security issues. More specifically, it is possible for an attacker to manipulate end-to-end protocols to defeat the low-latency feature of L4S nodes. In this paper, we analyze the set of weaknesses in L4S that could be exploited by an attacker to perform a set of malicious actions whose purpose is to defeat the low-latency.