BACKGROUND Central venous catheters (CVCs) play an indispensable role in clinical practice. Catheter malposition and tip migration can lead to severe complications. The authors present a case illustrating the endovascular management of inadvertent marginal sinus cannulation after an internal jugular vein (IJV) catheter tip migration. OBSERVATIONS A triple-lumen CVC was inserted without complications into the right IJV of a patient undergoing a repeat sternotomy for aortic valve replacement. Two weeks postinsertion, it was discovered that the tip had migrated superiorly, terminating below the torcula in the posterior fossa. In the interventional suite, a three-dimensional venogram confirmed the inadvertent marginal sinus cannulation. The catheter was carefully retracted to the sigmoid sinus to preserve the option of catheter exchange if embolization became necessary. After a subsequent venogram, which displayed an absence of contrast extravasation, the entire catheter was safely removed. The patient tolerated the procedure well. LESSONS Clinicians must be vigilant of catheter tip migration and malposition risks. Relying solely on postinsertion radiographs is insufficient. Once identified, prompt management of the malpositioned catheter is paramount in reducing morbidity and mortality and improving patient outcomes. Removing a malpositioned catheter constitutes a critical step, best performed by a specialized team under angiographic visualization.