Score: 2

Membership Inference on LLMs in the Wild

Published: January 16, 2026 | arXiv ID: 2601.11314v1

By: Jiatong Yi, Yanyang Li

Potential Business Impact:

Finds if private info was in AI's training.

Business Areas:
Machine Learning Artificial Intelligence, Data and Analytics, Software

Membership Inference Attacks (MIAs) act as a crucial auditing tool for the opaque training data of Large Language Models (LLMs). However, existing techniques predominantly rely on inaccessible model internals (e.g., logits) or suffer from poor generalization across domains in strict black-box settings where only generated text is available. In this work, we propose SimMIA, a robust MIA framework tailored for this text-only regime by leveraging an advanced sampling strategy and scoring mechanism. Furthermore, we present WikiMIA-25, a new benchmark curated to evaluate MIA performance on modern proprietary LLMs. Experiments demonstrate that SimMIA achieves state-of-the-art results in the black-box setting, rivaling baselines that exploit internal model information.

Repos / Data Links

Page Count
11 pages

Category
Computer Science:
Computation and Language