Jaechul Roh (노재철)

Ph.D. Candidate in Computer Science

University of Massachusetts Amherst

jroh [AT] cs.umass.edu

About

I am a Ph.D. candidate in computer science at the University of Massachusetts Amherst, advised by Amir Houmansadr. I also closely collaborate with Eugene Bagdasarian and am affiliated with SPIN Lab and the UMass AI Security Lab. My research focuses on the safety and security of AI models and agents. I investigate modality-specific threats and vulnerabilities in multimodal generative and agentic systems across audio, text, and vision, with work published at NeurIPS, USENIX Security, and COLM. My current research explores speech-based persuasion attacks on AI agents and speaker authorization in voice-driven agents, including how vocal cues and unauthorized speakers affect agent decisions, tool use, and adherence to security policies.

I have collaborated with researchers at Google DeepMind and Qualcomm. Most recently, I completed a research internship at Dolby Laboratories, where I investigated interruption-induced safety failures in real-time full-duplex speech models. Previously, I interned at Brave Software, studying privacy leakage and sensitive information oversharing in autonomous web agents.

I earned my M.S. in computer science from UMass Amherst in 2026 and my B.Eng. in computer engineering from the Hong Kong University of Science and Technology (HKUST) in 2023, where my final year thesis was advised by Jun Zhang.

Education

University of Massachusetts AmherstSeptember 2023 - Present

Ph.D. in Computer Science

University of Massachusetts AmherstSeptember 2023 - May 2026

M.S. in Computer Science

The Hong Kong University of Science and Technology Sept. 2017 - May 2023

B.Eng. Computer Engineering

Selected Publications

For the full list, see Google Scholar.
* indicates equal contribution.

DuplexJail: Spoken Interruption Attacks on Full-Duplex Speech Models

Jaechul Roh, Deepak Chandran, Amir Houmansadr, Andrea Fanelli

arXiv

Benign Fine-Tuning Breaks Safety Alignment in Audio LLMs

Jaechul Roh, Virat Shejwalkar, Amir Houmansadr

arXiv

CodecAttack: Codec-Robust Latent-Space Prompt-Injection Attacks on Audio LLMs

Jaechul Roh, Jean-Philippe Monteuuis, Jonathan Petit, Amir Houmansadr

arXiv

Multilingual and Multi-Accent Jailbreaking of Audio LLMs

Jaechul Roh, Virat Shejwalkar, Amir Houmansadr

COLM 2025

Backdooring Bias (B²) into Stable Diffusion Models

Ali Naseh, Jaechul Roh, Eugene Bagdasaryan, Amir Houmansadr

USENIX Security 2025

OSLO: One-Shot Label-Only Membership Inference Attacks

Yuefeng Peng, Jaechul Roh, Subhransu Maji, Amir Houmansadr

NeurIPS 2024

Bob's Confetti : Phonetic Memorization Attacks in Music and Video Generation

Jaechul Roh*, Zachary Novack*, Yuefeng Peng, Niloofar Mireshghallah, Taylor Berg-Kirkpatrick, Amir Houmansadr

arXiv

OverThink: Slowdown Attacks on Reasoning LLMs

Abhinav Kumar, Jaechul Roh, Ali Naseh, Marezna Karpinska, Mohit Iyyer, Amir Houmansadr, Eugene Bagdasaryan

arXiv

SPILLage: Agentic Oversharing on the Web

Jaechul Roh, Eugene Bagdasarian, Hamed Haddadi, Ali Shahin Shamsabadi

arXiv

Blog Posts

Nicholas Carlini delivering his invited talk at COLM 2025, photographed by Jaechul Roh
Thoughts on COLM 2025

Reflections from Montreal on language-model safety, generative interfaces, and human-centered AI risks.

Academic Service

Vitæ

Full Resume in PDF.

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