The escalation of missile warfare between Iran and Israel has intensified legal debates concerning the regulation of armed conflict under international law. This article examines these challenges through the Iran–Israel confrontation, with a particular focus on the large-scale missile exchanges in June 2025 and the renewed escalation in February 2026. The study demonstrates how contemporary warfare methods, including ballistic and cruise missiles, armed drones, and cyber operations, strain existing legal frameworks. It evaluates the legality of these developments under the United Nations Charter, particularly the prohibition on the use of force under Article 2(4) and the right of self-defense under Article 51, alongside the application of international humanitarian law principles of distinction, proportionality, and precautions in attack. By analyzing these developments, the article identifies doctrinal and operational gaps in current legal regimes and argues for adaptive legal mechanisms to address the challenges of modern missile warfare.

1. Introduction
2. Historical Background of the Iran–Israel Conflict
3. Legal Framework governing the Use of Force inthe Israel-Iran Conflict
4. The Israel–Iran Escalations of 2025 and 2026:Self-defense, Targeted Killing, and theEscalation of Hostilities
    A. June 2025 Escalation: Israeli Strikes and Iranian Response
    B. The War of February 2026: Targeted Killing, Self-defense, and Conflict Expansion
5. Conclusion

• Nehaluddin Ahmad(Professor of Law at Faculty of Law Sultan Haji Hassanal Bolkiah, University Islam Sultan Sharif Ali (UNISSA), Brunei Darussalam)
• Faizan Mustafa(Vice-Chancellor, Chanakya National Law University (CNLU), Patna, India)
• Faizah Rahim(Research Assistant, Tutor and Ph.D. candidate at Faculty of Law Sultan Haji Hassanal Bolkiah, Sultan Sharif Ali Islamic University (UNISSA), Brunei Darussalam)