Quantifying Privacy Risks of Masked Language Models Using Membership Inference Attacks
On the map: LLM safety and security → Membership inference attacks
Abstract (arXiv)
The wide adoption and application of Masked language models~(MLMs) on sensitive data (from legal to medical) necessitates a thorough quantitative investigation into their privacy vulnerabilities -- to what extent do MLMs leak information about their training data? Prior attempts at measuring leakage of MLMs via membership inference attacks have been inconclusive, implying the potential robustness of MLMs to privacy attacks. In this work, we posit that prior attempts were inconclusive because they based their attack solely on the MLM's model score. We devise a stronger membership inference attack based on likelihood ratio hypothesis testing that involves an additional reference MLM to more accurately quantify the privacy risks of memorization in MLMs. We show that masked language models are extremely susceptible to likelihood ratio membership inference attacks: Our empirical results, on models trained on medical notes, show that our attack improves the AUC of prior membership inference attacks from 0.66 to an alarmingly high 0.90 level, with a significant improvement in the low-error region: at 1% false positive rate, our attack is 51X more powerful than prior work.
Key facts. Cited by 168 papers in the map (data through 7 Oct 2026). Placed in Membership inference attacks, one of 12 directions in LLM safety and security. Builds on 35 of its 47 references that are in the map. First posted on arXiv 8 Mar 2022.
Builds on
35 of 47 references.
Closest ancestors · 4
Same direction, newest first
- 2021Membership Inference Attacks From First Principles7 Dec
- 2021Enhanced Membership Inference Attacks against Machine Learning Models18 Nov
- 2021Membership Inference on Word Embedding and Beyond21 Jun
- 2021Membership Inference Attack Susceptibility of Clinical Language Models16 Apr
Other references · 31
- 2018BERT: Pre-training of Deep Bidirectional Transformers for Language Understandingcited by 40,204
- 2019RoBERTa: A Robustly Optimized BERT Pretraining Approachcited by 13,266
- 2019BERTScore: Evaluating Text Generation with BERTcited by 5,462
- 2018GLUE: A Multi-Task Benchmark and Analysis Platform for Natural Language Understandingcited by 4,854
- 2016Deep Learning with Differential Privacycited by 2,682
- 2016Membership Inference Attacks against Machine Learning Modelscited by 2,221
- 2020Extracting Training Data from Large Language Modelscited by 2,144
- 2019BioBERT: a pre-trained biomedical language representation model for biomedical text miningcited by 1,935
- 2020Domain-Specific Language Model Pretraining for Biomedical Natural Language Processingcited by 996
- 2018The Secret Sharer: Evaluating and Testing Unintended Memorization in Neural Networkscited by 847
- 2020A Primer in BERTology: What we know about how BERT workscited by 807
- 2022Quantifying Memorization Across Neural Language Modelscited by 755
19 more
- 2018ML-Leaks: Model and Data Independent Membership Inference Attacks and Defenses on Machine Learning Modelscited by 475
- 2022Deduplicating Training Data Mitigates Privacy Risks in Language Modelscited by 309
- 2019Transfer Learning in Biomedical Natural Language Processing: An Evaluation of BERT and ELMo on Ten Benchmarking Datasetscited by 298
- 2020Information Leakage in Embedding Modelscited by 199
- 2022What Does it Mean for a Language Model to Preserve Privacy?cited by 194
- 2021Adversary Instantiation: Lower Bounds for Differentially Private Machine Learningcited by 193
- 2020FinBERT: A Pretrained Language Model for Financial Communicationscited by 161
- 2019Updates-Leak: Data Set Inference and Reconstruction Attacks in Online Learningcited by 117
- 2020Revisiting Membership Inference Under Realistic Assumptionscited by 108
- 2021Does BERT Pretrained on Clinical Notes Reveal Sensitive Data?cited by 91
- 2019Analyzing Information Leakage of Updates to Natural Language Modelscited by 89
- 2016De-identification of Patient Notes with Recurrent Neural Networkscited by 88
- 2020Privacy in Deep Learning: A Surveycited by 70
- 2019Membership Inference Attacks on Sequence-to-Sequence Models: Is My Data In Your Machine Translation System?cited by 68
- 2020ML Privacy Meter: Aiding Regulatory Compliance by Quantifying the Privacy Risks of Machine Learningcited by 66
- 2021Exposing the Implicit Energy Networks behind Masked Language Models via Metropolis--Hastingscited by 37
- 2021Privacy Regularization: Joint Privacy-Utility Optimization in Language Modelscited by 29
- 2017Towards Measuring Membership Privacycited by 27
- 2018Auditing Data Provenance in Text-Generation Modelscited by 5
Built on by
Citing papers per year: 2022: 6; 2023: 31; 2024: 56; 2025: 46; 2026: 29.
168 papers.
Sort:
By area:
- 2023"Do Anything Now": Characterizing and Evaluating In-The-Wild Jailbreak Prompts on Large Language Modelscited by 457
- 2023A Survey on Large Language Model (LLM) Security and Privacy: The Good, the Bad, and the Uglycited by 380
- 2023Detecting Pretraining Data from Large Language Modelscited by 375
- 2023Analyzing Leakage of Personally Identifiable Information in Language Modelscited by 278
- 2023Membership Inference Attacks against Language Models via Neighbourhood Comparisoncited by 249
- 2023Large Language Model Alignment: A Surveycited by 241
- 2022Memorization Without Overfitting: Analyzing the Training Dynamics of Large Language Modelscited by 218
- 2025Large Language Model Agent: A Survey on Methodology, Applications and Challengescited by 194
- 2024Do Membership Inference Attacks Work on Large Language Models?cited by 188
- 2024Security and Privacy Challenges of Large Language Models: A Surveycited by 179
- 2024Min-K%++: Improved Baseline for Detecting Pre-Training Data from Large Language Modelscited by 102
- 2022Truth Serum: Poisoning Machine Learning Models to Reveal Their Secretscited by 94
38 more
- 2024Investigating Data Contamination for Pre-training Language Modelscited by 91
- 2023Practical Membership Inference Attacks against Fine-tuned Large Language Models via Self-prompt Calibrationcited by 90
- 2024JailbreakRadar: Comprehensive Assessment of Jailbreak Attacks Against LLMscited by 87
- 2024Don't Listen To Me: Understanding and Exploring Jailbreak Prompts of Large Language Modelscited by 77
- 2024DE-COP: Detecting Copyrighted Content in Language Models Training Datacited by 72
- 2023Jais and Jais-chat: Arabic-Centric Foundation and Instruction-Tuned Open Generative Large Language Modelscited by 68
- 2024ReCaLL: Membership Inference via Relative Conditional Log-Likelihoodscited by 61
- 2023DP-OPT: Make Large Language Model Your Privacy-Preserving Prompt Engineercited by 56
- 2024UNDIAL: Self-Distillation with Adjusted Logits for Robust Unlearning in Large Language Modelscited by 49
- 2023Privacy in Large Language Models: Attacks, Defenses and Future Directionscited by 48
- 2024Operationalizing a Threat Model for Red-Teaming Large Language Models (LLMs)cited by 44
- 2022Memorization in NLP Fine-tuning Methodscited by 43
- 2023Training Data Extraction From Pre-trained Language Models: A Surveycited by 43
- 2023Bounding Training Data Reconstruction in DP-SGDcited by 42
- 2024Private Fine-tuning of Large Language Models with Zeroth-order Optimizationcited by 41
- 2024LLM-PBE: Assessing Data Privacy in Large Language Modelscited by 38
- 2023Ethicist: Targeted Training Data Extraction Through Loss Smoothed Soft Prompting and Calibrated Confidence Estimationcited by 36
- 2023User Inference Attacks on Large Language Modelscited by 36
- 2024Copyright Traps for Large Language Modelscited by 36
- 2023Smaller Language Models are Better Black-box Machine-Generated Text Detectorscited by 35
- 2024Elephants Never Forget: Memorization and Learning of Tabular Data in Large Language Modelscited by 34
- 2025Towards Label-Only Membership Inference Attack against Pre-trained Large Language Modelscited by 34
- 2024ConStat: Performance-Based Contamination Detection in Large Language Modelscited by 33
- 2023Identifying and Mitigating Privacy Risks Stemming from Language Models: A Surveycited by 30
- 2024Evading Data Contamination Detection for Language Models is (too) Easycited by 30
- 2024Evaluation data contamination in LLMs: how do we measure it and (when) does it matter?cited by 30
- 2024Undesirable Memorization in Large Language Models: A Surveycited by 29
- 2023Traces of Memorisation in Large Language Models for Codecited by 26
- 2024Large Model Based Agents: State-of-the-Art, Cooperation Paradigms, Security and Privacy, and Future Trendscited by 26
- 2024Does Data Contamination Detection Work (Well) for LLMs? A Survey and Evaluation on Detection Assumptionscited by 26
- 2024Digger: Detecting Copyright Content Mis-usage in Large Language Model Trainingcited by 24
- 2024Probing Language Models for Pre-training Data Detectioncited by 24
- 2024Data Contamination Calibration for Black-box LLMscited by 23
- 2024Deconstructing The Ethics of Large Language Models from Long-standing Issues to New-emerging Dilemmas: A Surveycited by 23
- 2024Generated Data with Fake Privacy: Hidden Dangers of Fine-tuning Large Language Models on Generated Datacited by 21
- 2024Con-ReCall: Detecting Pre-training Data in LLMs via Contrastive Decodingcited by 20
- 2024Context-Aware Membership Inference Attacks against Pre-trained Large Language Modelscited by 20
- 2025The Sum Leaks More Than Its Parts: Compositional Privacy Risks and Mitigations in Multi-Agent Collaborationcited by 19
50 most cited of 168 All 168 (JSON)
- 2026Only Pay What You Must Spend: On-Demand Privacy Budget Payment for Differentially Private RAG23 Sep 2026
- 2026Excess Separability: Nuisance-Controlled Residual-Stream Probing for Benchmark Contamination Detection12 Aug 2026
- 2026MuPPET: A Benchmark for Contextual Privacy of LLM Assistants in Multi-Party Conversations22 Jun 2026
- 2026Auditing Training Data in Domain-adapted LLMs: LoRA-MINT5 Jun 2026
- 2026A Full-Pipeline Framework for Evaluating Membership Inference Attacks in Machine Learning28 May 2026
- 2026Batch Normalization Amplifies Memorization and Privacy Risks23 May 2026
- 2026Pretraining Data Exposure in Large Language Models: A Survey of Membership Inference, Data Contamination, and Security Implications21 May 2026
- 2026Boundary-targeted Membership Inference Attacks on Safety Classifiers21 May 2026
- 2026JUMP: Single-Pass Membership Inference on Fine-Tuned Diffusion Language Models9 May 2026
- 2026PACZero: PAC-Private Fine-Tuning of Language Models via Sign Quantization7 May 2026
- 2026How Far Are VLMs from Privacy Awareness in the Physical World? An Empirical Study6 May 2026
- 2026Membership Inference Attacks for Retrieval Based In-Context Learning for Document Question Answering5 May 2026
38 more
- 2026ALDEN: Boosting Private Data Extraction from Retrieval-Augmented Generation Systems via Active Learning and Distribution Estimation10 Apr 2026
- 2026Towards Secure Retrieval-Augmented Generation: A Comprehensive Review of Threats, Defenses and Benchmarks23 Mar 2026
- 2026Assessing the Ability of Neural TTS Systems to Model Consonant-Induced F0 Perturbation22 Mar 2026
- 2026Privacy-Preserving End-to-End Full-Duplex Speech Dialogue Models9 Mar 2026
- 2026Benchmark of Benchmarks: Unpacking Influence and Code Repository Quality in LLM Safety Benchmarks3 Mar 2026
- 2026LoMime: Query-Efficient Membership Inference using Model Extraction in Label-Only Settings21 Feb 2026
- 2026Mitigating Gradient Inversion Risks in Language Models via Token Obfuscation11 Feb 2026
- 2026Agentic AI in Healthcare & Medicine: A Seven-Dimensional Taxonomy for Empirical Evaluation of LLM-based Agents4 Feb 2026
- 2026Provably Protecting Fine-Tuned LLMs from Training Data Extraction while Preserving Utility31 Jan 2026
- 2026Membership Inference Attacks Against Fine-tuned Diffusion Language Models27 Jan 2026
- 2026On the Evidentiary Limits of Membership Inference for Copyright Auditing19 Jan 2026
- 2026Gap-K%: Measuring Top-1 Prediction Gap for Detecting Pretraining Data16 Jan 2026
- 2026Model See, Model Do? Exposure-Aware Evaluation of Bug-vs-Fix Preference in Code LLMs15 Jan 2026
- 2026From Word Sequences to Behavioral Sequences: Adapting Modeling and Evaluation Paradigms for Longitudinal NLP12 Jan 2026
- 2026PDR: A Plug-and-Play Positional Decay Framework for LLM Pre-training Data Detection11 Jan 2026
- 2026Window-based Membership Inference Attacks Against Fine-tuned Large Language Models6 Jan 2026
- 2026UnPII: Unlearning Personally Identifiable Information with Quantifiable Exposure Risk5 Jan 2026
- 2025In-Context Probing for Membership Inference in Fine-Tuned Language Models18 Dec 2025
- 2025CTIGuardian: A Few-Shot Framework for Mitigating Privacy Leakage in Fine-Tuned LLMs15 Dec 2025
- 2025A Longitudinal Measurement of Privacy Policy Evolution for Large Language Models24 Nov 2025
- 2025As If We've Met Before: LLMs Exhibit Certainty in Recognizing Seen Files19 Nov 2025
- 2025Exploring Membership Inference Vulnerabilities in Clinical Large Language Models21 Oct 2025
- 2025Detecting Data Contamination from Reinforcement Learning Post-training for Large Language Models10 Oct 2025
- 2025The Model's Language Matters: A Comparative Privacy Analysis of LLMs9 Oct 2025
- 2025Detecting Distillation Data from Reasoning Models6 Oct 2025
- 2025Leave No TRACE: Black-box Detection of Copyrighted Dataset Usage in Large Language Models via Watermarking3 Oct 2025
- 2025Enterprise AI Must Enforce Participant-Aware Access Control18 Sep 2025
- 2025The Sum Leaks More Than Its Parts: Compositional Privacy Risks and Mitigations in Multi-Agent Collaboration16 Sep 2025
- 2025Beyond PII: How Users Attempt to Estimate and Mitigate Implicit LLM Inference15 Sep 2025
- 2025LLM in the Middle: A Systematic Review of Threats and Mitigations to Real-World LLM-based Systems12 Sep 2025
- 2025Active Membership Inference Test (aMINT): Enhancing Model Auditability with Multi-Task Learning9 Sep 2025
- 2025Privacy Risks in Time Series Forecasting: User- and Record-Level Membership Inference4 Sep 2025
- 2025Ensembling Membership Inference Attacks Against Tabular Generative Models2 Sep 2025
- 2025The Surprising Effectiveness of Membership Inference with Simple N-Gram Coverage13 Aug 2025
- 2025Win-k: Improved Membership Inference Attacks on Small Language Models2 Aug 2025
- 2025Uncovering Gradient Inversion Risks in Practical Language Model Training28 Jul 2025
- 2025LoRA-Leak: Membership Inference Attacks Against LoRA Fine-tuned Language Models24 Jul 2025
- 2025Unifying Re-Identification, Attribute Inference, and Data Reconstruction Risks in Differential Privacy9 Jul 2025
50 newest of 168 All 168 (JSON)
- 2023"Do Anything Now": Characterizing and Evaluating In-The-Wild Jailbreak Prompts on Large Language Modelscited by 457
- 2023Analyzing Leakage of Personally Identifiable Information in Language Modelscited by 278
- 2023Membership Inference Attacks against Language Models via Neighbourhood Comparisoncited by 249
- 2024Do Membership Inference Attacks Work on Large Language Models?cited by 188
- 2024Security and Privacy Challenges of Large Language Models: A Surveycited by 179
- 2023Practical Membership Inference Attacks against Fine-tuned Large Language Models via Self-prompt Calibrationcited by 90
- 2024JailbreakRadar: Comprehensive Assessment of Jailbreak Attacks Against LLMscited by 87
- 2024Don't Listen To Me: Understanding and Exploring Jailbreak Prompts of Large Language Modelscited by 77
- 2024ReCaLL: Membership Inference via Relative Conditional Log-Likelihoodscited by 61
- 2024UNDIAL: Self-Distillation with Adjusted Logits for Robust Unlearning in Large Language Modelscited by 49
- 2024Operationalizing a Threat Model for Red-Teaming Large Language Models (LLMs)cited by 44
- 2023Bounding Training Data Reconstruction in DP-SGDcited by 42
12 most cited of 62 All 62 (JSON)
- 2026Excess Separability: Nuisance-Controlled Residual-Stream Probing for Benchmark Contamination Detection12 Aug 2026
- 2026Auditing Training Data in Domain-adapted LLMs: LoRA-MINT5 Jun 2026
- 2026A Full-Pipeline Framework for Evaluating Membership Inference Attacks in Machine Learning28 May 2026
- 2026Pretraining Data Exposure in Large Language Models: A Survey of Membership Inference, Data Contamination, and Security Implications21 May 2026
- 2026Boundary-targeted Membership Inference Attacks on Safety Classifiers21 May 2026
- 2026Membership Inference Attacks for Retrieval Based In-Context Learning for Document Question Answering5 May 2026
- 2026Benchmark of Benchmarks: Unpacking Influence and Code Repository Quality in LLM Safety Benchmarks3 Mar 2026
- 2026LoMime: Query-Efficient Membership Inference using Model Extraction in Label-Only Settings21 Feb 2026
- 2026On the Evidentiary Limits of Membership Inference for Copyright Auditing19 Jan 2026
- 2026Window-based Membership Inference Attacks Against Fine-tuned Large Language Models6 Jan 2026
- 2026UnPII: Unlearning Personally Identifiable Information with Quantifiable Exposure Risk5 Jan 2026
- 2025In-Context Probing for Membership Inference in Fine-Tuned Language Models18 Dec 2025
12 newest of 62 All 62 (JSON)
- 2025Large Language Model Agent: A Survey on Methodology, Applications and Challengescited by 194
- 2025The Sum Leaks More Than Its Parts: Compositional Privacy Risks and Mitigations in Multi-Agent Collaborationcited by 19
- 2025A Longitudinal Measurement of Privacy Policy Evolution for Large Language Modelscited by 2
- 2026MuPPET: A Benchmark for Contextual Privacy of LLM Assistants in Multi-Party Conversationscited by 2
- 2026Agentic AI in Healthcare & Medicine: A Seven-Dimensional Taxonomy for Empirical Evaluation of LLM-based Agentscited by 1
- 2026MuPPET: A Benchmark for Contextual Privacy of LLM Assistants in Multi-Party Conversations22 Jun 2026
- 2026Agentic AI in Healthcare & Medicine: A Seven-Dimensional Taxonomy for Empirical Evaluation of LLM-based Agents4 Feb 2026
- 2025A Longitudinal Measurement of Privacy Policy Evolution for Large Language Models24 Nov 2025
- 2025The Sum Leaks More Than Its Parts: Compositional Privacy Risks and Mitigations in Multi-Agent Collaboration16 Sep 2025
- 2025Large Language Model Agent: A Survey on Methodology, Applications and Challenges27 Mar 2025
- 2025Membership Inference Attacks on Large-Scale Models: A Surveycited by 17
- 2025Watch Out Your Album! On the Inadvertent Privacy Memorization in Multi-Modal Large Language Modelscited by 3
- 2025DIS-CO: Discovering Copyrighted Content in VLMs Training Datacited by 1
- 2026How Far Are VLMs from Privacy Awareness in the Physical World? An Empirical Studycited by 0
- 2026How Far Are VLMs from Privacy Awareness in the Physical World? An Empirical Study6 May 2026
- 2025Membership Inference Attacks on Large-Scale Models: A Survey25 Mar 2025
- 2025Watch Out Your Album! On the Inadvertent Privacy Memorization in Multi-Modal Large Language Models3 Mar 2025
- 2025DIS-CO: Discovering Copyrighted Content in VLMs Training Data24 Feb 2025
- 2026Towards Secure Retrieval-Augmented Generation: A Comprehensive Review of Threats, Defenses and Benchmarkscited by 3
- 2026ALDEN: Boosting Private Data Extraction from Retrieval-Augmented Generation Systems via Active Learning and Distribution Estimationcited by 0
- 2026Only Pay What You Must Spend: On-Demand Privacy Budget Payment for Differentially Private RAGcited by 0
- 2026Only Pay What You Must Spend: On-Demand Privacy Budget Payment for Differentially Private RAG23 Sep 2026
- 2026ALDEN: Boosting Private Data Extraction from Retrieval-Augmented Generation Systems via Active Learning and Distribution Estimation10 Apr 2026
- 2026Towards Secure Retrieval-Augmented Generation: A Comprehensive Review of Threats, Defenses and Benchmarks23 Mar 2026
- 2023Large Language Model Alignment: A Surveycited by 241
- 2023Large Language Model Alignment: A Survey26 Sep 2023
- 2025Detecting Distillation Data from Reasoning Modelscited by 3
- 2025Detecting Distillation Data from Reasoning Models6 Oct 2025
- 2023A Survey on Large Language Model (LLM) Security and Privacy: The Good, the Bad, and the Uglycited by 380
- 2023Detecting Pretraining Data from Large Language Modelscited by 375
- 2022Memorization Without Overfitting: Analyzing the Training Dynamics of Large Language Modelscited by 218
- 2024Min-K%++: Improved Baseline for Detecting Pre-Training Data from Large Language Modelscited by 102
- 2022Truth Serum: Poisoning Machine Learning Models to Reveal Their Secretscited by 94
- 2024Investigating Data Contamination for Pre-training Language Modelscited by 91
- 2024DE-COP: Detecting Copyrighted Content in Language Models Training Datacited by 72
- 2023Jais and Jais-chat: Arabic-Centric Foundation and Instruction-Tuned Open Generative Large Language Modelscited by 68
- 2023DP-OPT: Make Large Language Model Your Privacy-Preserving Prompt Engineercited by 56
- 2023Privacy in Large Language Models: Attacks, Defenses and Future Directionscited by 48
- 2022Memorization in NLP Fine-tuning Methodscited by 43
- 2023Training Data Extraction From Pre-trained Language Models: A Surveycited by 43
12 most cited of 89 All 89 (JSON)
- 2026Batch Normalization Amplifies Memorization and Privacy Risks23 May 2026
- 2026PACZero: PAC-Private Fine-Tuning of Language Models via Sign Quantization7 May 2026
- 2026Assessing the Ability of Neural TTS Systems to Model Consonant-Induced F0 Perturbation22 Mar 2026
- 2026Privacy-Preserving End-to-End Full-Duplex Speech Dialogue Models9 Mar 2026
- 2026Mitigating Gradient Inversion Risks in Language Models via Token Obfuscation11 Feb 2026
- 2026Provably Protecting Fine-Tuned LLMs from Training Data Extraction while Preserving Utility31 Jan 2026
- 2026Gap-K%: Measuring Top-1 Prediction Gap for Detecting Pretraining Data16 Jan 2026
- 2026Model See, Model Do? Exposure-Aware Evaluation of Bug-vs-Fix Preference in Code LLMs15 Jan 2026
- 2026From Word Sequences to Behavioral Sequences: Adapting Modeling and Evaluation Paradigms for Longitudinal NLP12 Jan 2026
- 2026PDR: A Plug-and-Play Positional Decay Framework for LLM Pre-training Data Detection11 Jan 2026
- 2025As If We've Met Before: LLMs Exhibit Certainty in Recognizing Seen Files19 Nov 2025
- 2025Detecting Data Contamination from Reinforcement Learning Post-training for Large Language Models10 Oct 2025
12 newest of 89 All 89 (JSON)