https://finance.yahoo.com/news/vodafone-found-hidden-backdoors-huawei-064512773.html

Vodafone asked Huawei to remove backdoors in home internet routers in 2011 and received assurances from the supplier that the issues were fixed, but further testing revealed that the security vulnerabilities remained, the documents show. Vodafone also identified backdoors in parts of its fixed-access network known as optical service nodes, which are responsible for transporting internet traffic over optical fibers, and other parts called broadband network gateways, which handle subscriber authentication and access to the internet, the people said. The people asked not to be identified because the matter was confidential.

A backdoor, in cybersecurity terms, is a method of bypassing security controls to access a computer system or encrypted data. While backdoors can be common in some network equipment and software because developers create them to manage the gear, they can be exploited by attackers. In Vodafone’s case, the risks included possible third-party access to a customer's personal computer and home network, according to the internal documents.