activity
20242026
most citedMachine Against the RAG: Jamming Retrieval-Augmented Generation with Blocker Documents

2 citations · 5 across the 16 of their papers we have counts for

collaborators

18 papers

cs.AI2026

Speculative Probing: LLM Monitoring at Speculative-Decoding Cost

Collin Zhang, Tingwei Zhang, Vitaly Shmatikov

Real-time classification during language model inference is valuable for safety filtering, behavioral analysis, and model monitoring, but current approaches force a trade-off betwe…

cs.CL2026

Agent Meltdowns: The Road to Hell Is Paved with Helpful Agents

Rishi Jha, Harold Triedman, Arkaprabha Bhattacharya +1

Agents operating with computer and Web use inevitably encounter errors: inaccessible webpages, missing files, local and remote misconfigurations, etc. These errors do not thwart ag…

cs.CR2026

Deep-Research Agents Can Be Poisoned via User-Generated Content

Tingwei Zhang, Harold Triedman, Vitaly Shmatikov

Deep-research agents are an alternative to conventional Web search. They use multi-agent pipelines to issue multiple Web searches related to user queries, retrieve relevant content…

cs.CR2026

How to Steal Reasoning Without Reasoning Traces

Tingwei Zhang, John X. Morris, Vitaly Shmatikov

Many large language models (LLMs) use reasoning to generate responses but do not reveal their full reasoning traces (a.k.a. chains of thought), instead outputting only final answer…

cs.LG2026

Learning to Detect Language Model Training Data via Active Reconstruction

Junjie Oscar Yin, John X. Morris, Vitaly Shmatikov +2

Detecting LLM training data is generally framed as a membership inference attack (MIA) problem. However, conventional MIAs operate passively on fixed model weights, using log-likel…

cs.LG2025

Breaking and Fixing Defenses Against Control-Flow Hijacking in Multi-Agent Systems

Rishi Jha, Harold Triedman, Justin Wagle +1

Control-flow hijacking attacks manipulate orchestration mechanisms in multi-agent systems into performing unsafe actions that compromise the system and exfiltrate sensitive informa…

cs.LG2025

MillStone: How Open-Minded Are LLMs?

Harold Triedman, Vitaly Shmatikov

Large language models equipped with Web search, information retrieval tools, and other agentic capabilities are beginning to supplant traditional search engines. As users start to…

cs.CL2025

Approximating Language Model Training Data from Weights

John X. Morris, Junjie Oscar Yin, Woojeong Kim +2

Modern language models often have open weights but closed training data. We formalize the problem of data approximation from model weights and propose several baselines and metrics…

cs.LG2025

Harnessing the Universal Geometry of Embeddings

Rishi Jha, Collin Zhang, Vitaly Shmatikov +1

We introduce the first method for translating text embeddings from one vector space to another without any paired data, encoders, or predefined sets of matches. Our unsupervised ap…

cs.CL2025

Universal Zero-shot Embedding Inversion

Collin Zhang, John X. Morris, Vitaly Shmatikov

Embedding inversion, i.e., reconstructing text given its embedding and black-box access to the embedding encoder, is a fundamental problem in both NLP and security. From the NLP pe…

cs.CR2025

Multi-Agent Systems Execute Arbitrary Malicious Code

Harold Triedman, Rishi Jha, Vitaly Shmatikov

Multi-agent systems coordinate LLM-based agents to perform tasks on users' behalf. In real-world applications, multi-agent systems will inevitably interact with untrusted inputs, s…

cs.CR2025

Rerouting LLM Routers

Avital Shafran, Roei Schuster, Thomas Ristenpart +1

LLM routers aim to balance quality and cost of generation by classifying queries and routing them to a cheaper or more expensive LLM depending on their complexity. Routers represen…

cs.CR2024

Adversarial Hubness in Multi-Modal Retrieval

Tingwei Zhang, Fnu Suya, Rishi Jha +2

Hubness is a phenomenon in high-dimensional vector spaces where a point from the natural distribution is unusually close to many other points. This is a well-known problem in infor…

cs.LG2024★ 2 cited

Machine Unlearning Doesn't Do What You Think: Lessons for Generative AI Policy and Research

A. Feder Cooper, Christopher A. Choquette-Choo, Miranda Bogen +34

"Machine unlearning" is a popular proposed solution for mitigating the existence of content in an AI model that is problematic for legal or moral reasons, including privacy, copyri…

cs.CL2024

Adversarial Decoding: Generating Readable Documents for Adversarial Objectives

Collin Zhang, Tingwei Zhang, Vitaly Shmatikov

We design, implement, and evaluate adversarial decoding, a new, generic text generation technique that produces readable documents for different adversarial objectives. Prior metho…

cs.CR2024★ 1 cited

Self-interpreting Adversarial Images

Tingwei Zhang, Collin Zhang, John X. Morris +2

We introduce a new type of indirect, cross-modal injection attacks against visual language models that enable creation of self-interpreting images. These images contain hidden "met…

cs.CR2024★ 2 cited

Machine Against the RAG: Jamming Retrieval-Augmented Generation with Blocker Documents

Avital Shafran, Roei Schuster, Vitaly Shmatikov

Retrieval-augmented generation (RAG) systems respond to queries by retrieving relevant documents from a knowledge database and applying an LLM to the retrieved documents. We demons…

cs.CL2024

Extracting Prompts by Inverting LLM Outputs

Collin Zhang, John X. Morris, Vitaly Shmatikov

We consider the problem of language model inversion: given outputs of a language model, we seek to extract the prompt that generated these outputs. We develop a new black-box metho…