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Pengfei He

21 accepted papers

2026

Co-RedTeam: Orchestrated Security Discovery and Exploitation with LLM Agents

ICML 2026poster

Large language models (LLMs) have shown promise in assisting cybersecurity tasks, yet existing approaches struggle with automatic vulnerability discovery and exploitation due to limited interaction, weak execution grounding, and a lack of experience reuse. We propose Co-RedTeam, a security-aware mul…

Cited by 0SourceScholar
2026

TRAJECT-Bench:A Trajectory-Aware Benchmark for Evaluating Agentic Tool Use

ICLR 2026poster

Large language model (LLM)-based agents increasingly rely on tool use to complete real-world tasks. While existing works evaluate the LLMs' tool use capability, they largely focus on the final answers yet overlook the detailed tool usage trajectory, i.e., whether tools are selected, parameterized, a…

Cited by 0SourcecodeScholar
2025

A Theoretical Understanding of Chain-of-Thought: Coherent Reasoning and Error-Aware Demonstration

AISTATS 2025poster

Few-shot Chain-of-Thought (CoT) prompting has demonstrated strong performance in improving the reasoning capabilities of large language models (LLMs). While theoretical investigations have been conducted to understand CoT, the underlying transformer used in these studies isolates the CoT reasoning p…

Cited by 0SourceScholar
2025

Advancing Reasoning with Off-the-Shelf LLMs: A Semantic Structure Perspective

EMNLP 2025

Large Language Models (LLMs) have shown strong capabilities in zero-shot reasoning and generalization to new tasks. However, the zero-shot performance of general LLMs on complex tasks, such as multi-hop reasoning, remains suboptimal, while reasoning LLMs suffer from hallucinations and unfaithfulness

Cited by 0SourcePDFScholar
2025

Memory Injection Attacks on LLM Agents via Query-Only Interaction

NeurIPS 2025poster

Agents powered by large language models (LLMs) have demonstrated strong capabilities in a wide range of complex, real-world applications. However, LLM agents with a compromised memory bank may easily produce harmful outputs when the past records retrieved for demonstration are malicious. In this pap…

Cited by 0SourceScholar
2025

Mitigating the Privacy Issues in Retrieval-Augmented Generation (RAG) via Pure Synthetic Data

EMNLP 2025

Retrieval-augmented generation (RAG) enhances the outputs of language models by integrating relevant information retrieved from external knowledge sources. However, when the retrieval process involves private data, RAG systems may face severe privacy risks, potentially leading to the leakage of sens

2025

Red-Teaming LLM Multi-Agent Systems via Communication Attacks

ACL 2025finding

Large Language Model-based Multi-Agent Systems (LLM-MAS) have revolutionized complex problem-solving capability by enabling sophisticated agent collaboration through message-based communications. While the communication framework is crucial for agent coordination, it also introduces a critical yet u…

Cited by 0SourcePDFScholar
2025

Stepwise Perplexity-Guided Refinement for Efficient Chain-of-Thought Reasoning in Large Language Models

ACL 2025finding

Chain-of-Thought (CoT) reasoning, which breaks down complex tasks into intermediate reasoning steps, has significantly enhanced the performance of large language models (LLMs) on challenging tasks. However, the detailed reasoning process in CoT often incurs long generation times and high computation…

Cited by 0SourcePDFScholar
2025

Superiority of Multi-Head Attention: A Theoretical Study in Shallow Transformers in In-Context Linear Regression

AISTATS 2025poster

We present a theoretical analysis of the performance of transformer with softmax attention in in-context learning with linear regression tasks. While the existing theoretical literature predominantly focuses on providing convergence upper bounds to show that trained transformers with single-/multi-h…

Cited by 0SourceScholar
2025

Towards Context-Robust LLMs: A Gated Representation Fine-tuning Approach

ACL 2025long

Large Language Models (LLMs) enhanced with external contexts, such as through retrieval-augmented generation (RAG), often face challenges in handling imperfect evidence. They tend to over-rely on external knowledge, making them vulnerable to misleading and unhelpful contexts. To address this, we pro…

Cited by 0SourcePDFScholar
2024

An Integrated Position-velocity-force Method for Safety-enhanced Shared Control in Robot-assisted Surgical Cutting

ICRA 2024poster

Numerous studies have emphasized the application of autonomous intelligence in human-robot shared control to enhance surgical convenience and efficiency. However, the neglect of human dominance may reduce surgical safety. This paper developed a safety-enhanced human-robot shared control method by in…

Cited by 0SourceScholar
2024

Exploring Memorization in Fine-tuned Language Models

ACL 2024long

Large language models (LLMs) have shown great capabilities in various tasks but also exhibited memorization of training data, raising tremendous privacy and copyright concerns. While prior works have studied memorization during pre-training, the exploration of memorization during fine-tuning is rath…

Cited by 26SourcePDFScholar
2024

On the Generalization of Training-based ChatGPT Detection Methods

EMNLP 2024finding

Large language models, such as ChatGPT, achieve amazing performance on various language processing tasks. However, they can also be exploited for improper purposes such as plagiarism or misinformation dissemination. Thus, there is an urgent need to detect the texts generated by LLMs. One type of mos…

2024

The Good and The Bad: Exploring Privacy Issues in Retrieval-Augmented Generation (RAG)

ACL 2024findings

Retrieval-augmented generation (RAG) is a powerful technique to facilitate language model generation with proprietary and private data, where data privacy is a pivotal concern. Whereas extensive research has demonstrated the privacy risks of large language models (LLMs), the RAG technique could pote…

2024

Towards Understanding Jailbreak Attacks in LLMs: A Representation Space Analysis

EMNLP 2024main

Large language models (LLMs) are susceptible to a type of attack known as jailbreaking, which misleads LLMs to output harmful contents. Although there are diverse jailbreak attack strategies, there is no unified understanding on why some methods succeed and others fail. This paper explores the behav…

2023

Probabilistic Categorical Adversarial Attack and Adversarial Training

ICML 2023poster

The studies on adversarial attacks and defenses have greatly improved the robustness of Deep Neural Networks (DNNs). Most advanced approaches have been overwhelmingly designed for continuous data such as images. However, these achievements are still hard to be generalized to categorical data. To bri…

Cited by 14SourcePDFScholar
2022

Rainier: Reinforced Knowledge Introspector for Commonsense Question Answering

EMNLP 2022main

Knowledge underpins reasoning. Recent research demonstrates that when relevant knowledge is provided as additional context to commonsense question answering (QA), it can substantially enhance the performance even on top of state-of-the-art. The fundamental challenge is where and how to find such kno…