As central bank digital currency projects move beyond the pilot phase and enter the regulatory phase in countries such as the United Arab Emirates, the issue of interoperability of these currencies and their conflict with traditional concepts of monetary sovereignty has become a legal challenge. This research aims to identify the existing legal gaps in national and international legal systems for the acceptance of central bank digital currencies as legal tender in cross-border transactions and to analyze its impact on power dynamics in the future multipolar financial system. The main question is, given the lack of a unified supranational framework, how should conflicts of monetary sovereignty in cross-border CBDC transactions be resolved? And what impact will these currencies have on the dominance of the dollar and the role of traditional financial institutions such as SWIFT? This research was conducted with a descriptive-analytical approach and with reference to international legal documents, reports from institutions such as the International Monetary Fund (IMF) and the Bank for International Settlements (BIS), as well as analysis of operational projects such as "mBridge." The findings show that despite the potential of central bank digital currencies to reduce costs and increase payment speed by eliminating intermediaries, the main challenge in the legal arena is the lack of uniform standards in the field of data privacy (such as conflict with Europe's GDPR) and dispute resolution mechanisms arising from transactions based on distributed ledgers. Furthermore, projects such as mBridge, as a tool for BRICS member countries to bypass the dollar-based system, confirm the formation of regional monetary blocs and the challenge to traditional monetary sovereignty. In conclusion, the transition from the current monetary system to a network of cross-border central bank digital currencies requires the creation of a "new legal architecture" at the supranational level; otherwise, legal and technical fragmentation will weaken financial stability and intensify geopolitical competition over the standardization of these currencies.