collaborators

6 papers

cs.LG2026

Humanity's Last Exam

Long Phan, Alice Gatti, Ziwen Han +1144

Benchmarks are important tools for tracking the rapid advancements in large language model (LLM) capabilities. However, benchmarks are not keeping pace in difficulty: LLMs now achi…

cs.CL2025

Improving LLM Safety Alignment with Dual-Objective Optimization

Xuandong Zhao, Will Cai, Tianneng Shi +4

Existing training-time safety alignment techniques for large language models (LLMs) remain vulnerable to jailbreak attacks. Direct preference optimization (DPO), a widely deployed…

cs.CL2025

Are You Getting What You Pay For? Auditing Model Substitution in LLM APIs

Will Cai, Tianneng Shi, Xuandong Zhao +1

Commercial Large Language Model (LLM) APIs create a fundamental trust problem: users pay for specific models but have no guarantee that providers deliver them faithfully. Providers…

cs.AI2025

The Geometry of Harmfulness in LLMs through Subconcept Probing

McNair Shah, Saleena Angeline, Adhitya Rajendra Kumar +5

Recent advances in large language models (LLMs) have intensified the need to understand and reliably curb their harmful behaviours. We introduce a multidimensional framework for pr…

cs.CR2025

PromptArmor: Simple yet Effective Prompt Injection Defenses

Tianneng Shi, Kaijie Zhu, Zhun Wang +13

Despite their potential, recent research has demonstrated that LLM agents are vulnerable to prompt injection attacks, where malicious prompts are injected into the agent's input, c…

cs.CR2025

Scaling Trends for Data Poisoning in LLMs

Dillon Bowen, Brendan Murphy, Will Cai +3

LLMs produce harmful and undesirable behavior when trained on datasets containing even a small fraction of poisoned data. We demonstrate that GPT models remain vulnerable to fine-t…