The work presents and investigates the method of calculating the probability of confidential message compromise during secure routing in infocommunication networks, fragments of which are transmitted by intersecting paths. In comparison with existing approaches, in particular with the well-known SPREAD method, which allows the routing of confidential message fragments only by disjoint paths, the proposed solution makes it possible to achieve more efficient usage of network and cyber resources when solving the secure routing problem. The methodology is based on a mathematical model for calculating the compromise probability of fragmented messages. It was improved to enable its application in networks with a more complex structure, where routing paths are represented not only by the series-parallel connection of links but also bridges may be present. The effectiveness of the presented solution regarding secure routing was evaluated by the indicator of the confidential message compromise probability using the mechanism of its fragmentation according to Shamir’s scheme. At the same time, unlike the well-known SPREAD approach, the presented technique does not require the preliminary calculation of the paths through which message fragments are transmitted, simplifying its implementation in practice. The analysis of the proposed method confirmed its higher efficiency compared to the SPREAD method, while the lower the values of the network link compromise probability, the greater the gain in terms of the message compromise probability, even in a small network with a small number of nodes, links, and only one bridge. The proposed technique is implemented as software prototypes of secure routing protocols in MATLAB and Python environments.