{"paper":{"title":"CornerCase: Automated Extremal Testing of Protocol Implementations using LLMs","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":[],"primary_cat":"cs.NI","authors_text":"George Varghese, Kuan Qian, Rathin Singha, Ryan Beckett, Siva Kesava Reddy Kakarla, Soheil Abbasloo, Srinath Saikrishnan, Todd Millstein, Tracy Zhao","submitted_at":"2026-06-28T00:25:50Z","abstract_excerpt":"Many software bugs in network protocol implementations arise near specification boundaries, such as inputs just within or outside allowed ranges, or messages that are valid in isolation but invalid in a given state. From the SSL Heartbleed exploit to TCP Christmas Tree packets, boundary inputs have repeatedly exposed critical weaknesses, yet remain under-tested by existing techniques such as fuzzing and model-based testing. We present CornerCase, an automated extremal testing approach that systematically targets such boundary behaviors. Our key idea is to decompose test generation into two sta"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2606.29124","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2606.29124/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}