Work

Before the Model Learns the Bug:Fuzzing RLVR Verifiers

Year: 2026
Type: preprint
Abstract: Reinforcement learning with verifiable rewards (RLVR) replaces human preference labels with executable reward functions such as math answer checkers, JSON tool-call validators, and code unit-test harnesses. That makes the reward partly a software artifact: if the verifier is wrong, optimization can learn the bug. We study this failure mode with a lightweight verifier-fuzzing framework that generates adversarial completions, compares buggy and stricter reference verifiers, logs paired decisions, and reports false-positive, false-negative, disagreement, exploit, and uncertainty metrics.
Author: Ray, Jaideep
Subfield: Software
Open Access status: green
OpenAlex ID: W7163279756
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