The cancellation of land ownership certificates often impacts third parties who have obtained their rights through valid and good faith transactions. This study aims to analyze the legal consequences faced by third parties following such cancellations, viewed through the lens of legal protection and liability theories. A normative juridical method was employed, using a case study approach—specifically, Decision Number 13/Pdt.G/2018/PN Jth. The findings indicate that the negative publication system in Indonesia's land registration process provides limited legal protection to third parties. The responsibility of sellers, as well as the importance of preventive and repressive legal protection, are key factors in addressing legal uncertainty.