Fuzzing RPKI Validators with Semantic and Structural Awareness

The Resource Public Key Infrastructure (RPKI) secures BGP routing by enabling validation of routing announcements via signed objects. Relying Party (RP) software, responsible for Route Origin Validation (ROV), is complex and error-prone, with over 20 vulnerabilities disclosed to date. These flaws could potentially compromise BGP security and affect routing decisions. We present RFuzz, a fuzzing framework that automatically uncovers subtle bugs in RP implementations by addressing two core challenges: (1) the semantic and structural complexity of RPKI inputs, and (2) the difficulty of detecting non-crashing behavioral deviations. RFuzz introduces a structured semantic mutator that ensures input validity and cross-file consistency using semantic templates and a grammar-based RPKI model, and a hybrid deviation monitor combining active canary injection with passive semantic checks across RPs. Evaluation shows RFuzz achieves 100% semantic validity and discovers 7 new flaws across three popular RP implementations, 6 of which have been confirmed and will be fixed by maintainers.