CVE-2026-53671

PREVAIL is a Polynomial-Runtime EBPF Verifier using an Abstract Interpretation Layer. Prior to version 0.2.4, the abstract transformer in prevail treats writes through a TCTX-typed base register as a silent no-op: domemstore in src/crab/ebpftransformer.cpp only models TSTACK stores, and the checker's TCTX bounds arm never tests AccessType::write. An attacker can craft an eBPF program that overwrites a context field (e.g., ctx->data), reload that field typed as T_PACKET, and dereference an attacker-controlled address — and prevail will report the program as safe. This issue has been patched in version 0.2.4.