Brain arteriovenous malformations (AVMs), cerebral cavernous malformations (CCMs), and intracranial aneurysms are major causes of hemorrhagic stroke, yet noninvasive therapies to prevent growth or rupture are lacking. Understanding the genetic basis of these malformations is critical for uncovering underlying mechanisms, developing targeted prevention strategies, and identifying novel therapeutic targets. This review highlights the causal genes and signaling pathways in AVMs, CCMs, and intracranial aneurysms, noting both their commonalities and differences. For AVMs, somatic mutations in the Ras/MAPK (mitogen-activated protein kinase) and MAPK/ERK (extracellular signal–regulated kinase) pathway are key, particularly in sporadic cases, whereas hereditary conditions like hereditary hemorrhagic telangiectasia and capillary malformation–AVM involve the TGF-β (transforming growth factor β), Ephrin receptor, and angiopoietin-VEGF (vascular endothelial growth factor) signaling pathways. In CC