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Main Authors: Min, Nay Myat, Pham, Long H., Zhang, Hongyu, Sun, Jun
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2601.14310
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author Min, Nay Myat
Pham, Long H.
Zhang, Hongyu
Sun, Jun
author_facet Min, Nay Myat
Pham, Long H.
Zhang, Hongyu
Sun, Jun
contents Single-pass hallucination detectors rely on internal telemetry (e.g., uncertainty, hidden-state geometry, and attention) of large language models, implicitly assuming hallucinations leave separable traces in these signals. We study a white-box, model-side adversary that fine-tunes lightweight LoRA adapters on the model while keeping the detector fixed, and introduce CORVUS, an efficient red-teaming procedure that learns to camouflage detector-visible telemetry under teacher forcing, including an embedding-space FGSM attention stress test. Trained on 1,000 out-of-distribution Alpaca instructions (<0.5% trainable parameters), CORVUS transfers to FAVA-Annotation across Llama-2, Vicuna, Llama-3, and Qwen2.5, and degrades both training-free detectors (e.g., LLM-Check) and probe-based detectors (e.g., SEP, ICR-probe), motivating adversary-aware auditing that incorporates external grounding or cross-model evidence.
format Preprint
id arxiv_https___arxiv_org_abs_2601_14310
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle CORVUS: Red-Teaming Hallucination Detectors via Internal Signal Camouflage in Large Language Models
Min, Nay Myat
Pham, Long H.
Zhang, Hongyu
Sun, Jun
Cryptography and Security
Artificial Intelligence
Single-pass hallucination detectors rely on internal telemetry (e.g., uncertainty, hidden-state geometry, and attention) of large language models, implicitly assuming hallucinations leave separable traces in these signals. We study a white-box, model-side adversary that fine-tunes lightweight LoRA adapters on the model while keeping the detector fixed, and introduce CORVUS, an efficient red-teaming procedure that learns to camouflage detector-visible telemetry under teacher forcing, including an embedding-space FGSM attention stress test. Trained on 1,000 out-of-distribution Alpaca instructions (<0.5% trainable parameters), CORVUS transfers to FAVA-Annotation across Llama-2, Vicuna, Llama-3, and Qwen2.5, and degrades both training-free detectors (e.g., LLM-Check) and probe-based detectors (e.g., SEP, ICR-probe), motivating adversary-aware auditing that incorporates external grounding or cross-model evidence.
title CORVUS: Red-Teaming Hallucination Detectors via Internal Signal Camouflage in Large Language Models
topic Cryptography and Security
Artificial Intelligence
url https://arxiv.org/abs/2601.14310