Machine Unlearning: Solutions and Challenges
On the map: LLM safety and security → Machine unlearning
Abstract (arXiv)
Machine learning models may inadvertently memorize sensitive, unauthorized, or malicious data, posing risks of privacy breaches, security vulnerabilities, and performance degradation. To address these issues, machine unlearning has emerged as a critical technique to selectively remove specific training data points' influence on trained models. This paper provides a comprehensive taxonomy and analysis of the solutions in machine unlearning. We categorize existing solutions into exact unlearning approaches that remove data influence thoroughly and approximate unlearning approaches that efficiently minimize data influence. By comprehensively reviewing solutions, we identify and discuss their strengths and limitations. Furthermore, we propose future directions to advance machine unlearning and establish it as an essential capability for trustworthy and adaptive machine learning models. This paper provides researchers with a roadmap of open problems, encouraging impactful contributions to address real-world needs for selective data removal.
Key facts. Cited by 85 papers in the map (data through 7 Oct 2026). Placed in Machine unlearning, one of 12 directions in LLM safety and security. Builds on 74 of its 139 references that are in the map. First posted on arXiv 14 Aug 2023.
Builds on
74 of 139 references.
Closest ancestors · 17
Same direction, newest first
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- 2022Deep Unlearning via Randomized Conditionally Independent Hessians15 Apr
- 2022Knowledge Removal in Sampling-based Bayesian Inference24 Mar
- 2022Markov Chain Monte Carlo-Based Machine Unlearning: Unlearning What Needs to be Forgotten28 Feb
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- 2021On the Necessity of Auditable Algorithmic Definitions for Machine Unlearning22 Oct
- 2021Unrolling SGD: Understanding Factors Influencing Machine Unlearning27 Sep
- 2021Machine Unlearning of Features and Labels26 Aug
- 2021Adaptive Machine Unlearning8 Jun
- 2021Remember What You Want to Forget: Algorithms for Machine Unlearning4 Mar
Other references · 57
- 2016Communication-Efficient Learning of Deep Networks from Decentralized Datacited by 7,592
- 2015Batch Normalization: Accelerating Deep Network Training by Reducing Internal Covariate Shiftcited by 6,979
- 2017A Unified Approach to Interpreting Model Predictionscited by 6,488
- 2016Pointer Sentinel Mixture Modelscited by 2,992
- 2016Membership Inference Attacks against Machine Learning Modelscited by 2,221
- 2017Understanding Black-box Predictions via Influence Functionscited by 1,714
- 2019Explainable Artificial Intelligence (XAI): Concepts, Taxonomies, Opportunities and Challenges toward Responsible AIcited by 1,543
- 2017Towards A Rigorous Science of Interpretable Machine Learningcited by 1,400
- 2019Machine Unlearningcited by 1,020
- 2018Overcoming catastrophic forgetting with hard attention to the taskcited by 672
- 2013Speech Recognition with Deep Recurrent Neural Networkscited by 666
- 2019Eternal Sunshine of the Spotless Net: Selective Forgetting in Deep Networkscited by 599
38 more
- 2019Certified Data Removal from Machine Learning Modelscited by 512
- 2020Graph Neural Networks in Recommender Systems: A Surveycited by 493
- 2019Making AI Forget You: Data Deletion in Machine Learningcited by 447
- 2014New insights and perspectives on the natural gradient methodcited by 435
- 2020Exploring Self-attention for Image Recognitioncited by 313
- 2021Membership Inference Attacks on Machine Learning: A Surveycited by 306
- 2020Descent-to-Delete: Gradient-Based Methods for Machine Unlearningcited by 303
- 2017Certified Defenses for Data Poisoning Attackscited by 288
- 2023Multimodal Deep Learningcited by 257
- 2020Approximate Data Deletion from Machine Learning Modelscited by 250
- 2020Auditing Differentially Private Machine Learning: How Private is Private SGD?cited by 213
- 2020When Machine Unlearning Jeopardizes Privacycited by 181
- 2020Forgetting Outside the Box: Scrubbing Deep Networks of Information Accessible from Input-Output Observationscited by 171
- 2020Mixed-Privacy Forgetting in Deep Networkscited by 158
- 2020DeltaGrad: Rapid retraining of machine learning modelscited by 143
- 2018Backdoor Embedding in Convolutional Neural Network Models via Invisible Perturbationcited by 131
- 2021Graph Unlearningcited by 129
- 2022The Privacy Onion Effect: Memorization is Relativecited by 128
- 2020Machine Unlearning for Random Forestscited by 125
- 2020Variational Bayesian Unlearningcited by 114
- 2022The Right to be Forgotten in Federated Learning: An Efficient Realization with Rapid Retrainingcited by 109
- 2021Federated Unlearning via Class-Discriminative Pruningcited by 108
- 2020On the Privacy Risks of Algorithmic Fairnesscited by 82
- 2021Proof-of-Learning: Definitions and Practicecited by 81
- 2019Measure Contribution of Participants in Federated Learningcited by 78
- 2021Practical Blind Membership Inference Attack via Differential Comparisonscited by 73
- 2021Manipulating SGD with Data Ordering Attackscited by 73
- 2022Recommendation Unlearningcited by 71
- 2022Backdoor Defense with Machine Unlearningcited by 61
- 2023GIF: A General Graph Unlearning Strategy via Influence Functioncited by 59
- 2020Learn to Forget: Machine Unlearning via Neuron Maskingcited by 56
- 2022PUMA: Performance Unchanged Model Augmentation for Training Data Removalcited by 56
- 2022FedRecover: Recovering from Poisoning Attacks in Federated Learning using Historical Informationcited by 53
- 2020Formalizing Data Deletion in the Context of the Right to be Forgottencited by 46
- 2021Survey: Leakage and Privacy at Inference Timecited by 44
- 2023GNNDelete: A General Strategy for Unlearning in Graph Neural Networkscited by 43
- 2022VeriFi: Towards Verifiable Federated Unlearningcited by 41
- 2023Heterogeneous Federated Knowledge Graph Embedding Learning and Unlearningcited by 39
50 most cited of 57 All 57 (JSON)
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Citing papers per year: 2023: 2; 2024: 22; 2025: 36; 2026: 25.
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- 2025Unlearning Comparator: A Visual Analytics System for Comparative Evaluation of Machine Unlearning Methodscited by 4
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- 2024GraphMU: Repairing Robustness of Graph Neural Networks via Machine Unlearningcited by 1
- 2024Instance-Level Difficulty: A Missing Perspective in Machine Unlearningcited by 1
- 2024Neural Corrective Machine Unrankingcited by 1
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- 2026Robust Industrial Cyber Physical Classification Using Neuromorphic Temporal Embeddings and Hybrid SNN XGBoost Under Machine Unlearning Attacks9 Sep 2026
- 2026Cross-Domain Generalization in Machine Unlearning via Label-Conditioned Energy Magnitude Regularization18 Aug 2026
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- 2026LLM Unlearning for Cyber Defense: A Survey on Methods, Challenges, and Emerging Threats23 Jun 2026
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- 2026Selective Capability Unlearning in End-to-End Spoken Language Understanding23 Jun 2026
- 2026Machine Unlearning for the XGBoost Model with Network Intrusion Datasets17 Jun 2026
- 2026SUPREME: A Multi-GPU Framework for Reproducible Image Unlearning Method Evaluation29 May 2026
- 2026Toward a Benchmark for Controllable Simulation of Imperfect Students with Large Language Models25 May 2026
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- 2026Understanding U.S. Users' Security and Privacy Transparency Needs for Consumer-Facing Generative AI19 Apr 2026
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- 2026Unlearning Evaluation through Subset Statistical Independence28 Feb 2026
- 2026FaLW: A Forgetting-aware Loss Reweighting for Long-tailed Unlearning26 Jan 2026
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- 2026A Robust Certified Machine Unlearning Method Under Distribution Shift11 Jan 2026
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- 2025How to Protect Models against Adversarial Unlearning?15 Jul 2025
- 2025Efficient Unlearning with Privacy Guarantees7 Jul 2025
- 2025Existing Large Language Model Unlearning Evaluations Are Inconclusive31 May 2025
- 2025"Alexa, can you forget me?" Machine Unlearning Benchmark in Spoken Language Understanding21 May 2025
- 2025A Unified Gradient-based Framework for Task-agnostic Continual Learning-Unlearning21 May 2025
- 2025DualOptim: Enhancing Efficacy and Stability in Machine Unlearning with Dual Optimizers22 Apr 2025
- 2025ForgetMe: Evaluating Selective Forgetting in Generative Models17 Apr 2025
- 2025SAEs Can Improve Unlearning: Dynamic Sparse Autoencoder Guardrails for Precision Unlearning in LLMs11 Apr 2025
50 newest of 85 All 85 (JSON)
- 2024Catastrophic Failure of LLM Unlearning via Quantizationcited by 76
- 2024Unified Gradient-Based Machine Unlearning with Remain Geometry Enhancementcited by 43
- 2024Threats, Attacks, and Defenses in Machine Unlearning: A Surveycited by 34
- 2024Towards Scalable Exact Machine Unlearning Using Parameter-Efficient Fine-Tuningcited by 25
- 2025SAEs Can Improve Unlearning: Dynamic Sparse Autoencoder Guardrails for Precision Unlearning in LLMscited by 21
- 2024Learning to Unlearn for Robust Machine Unlearningcited by 19
- 2024Is Retain Set All You Need in Machine Unlearning? Restoring Performance of Unlearned Models with Out-Of-Distribution Imagescited by 18
- 2025LLM Unlearning with LLM Beliefscited by 17
- 2025NoT: Federated Unlearning via Weight Negationcited by 15
- 2023DUCK: Distance-based Unlearning via Centroid Kinematicscited by 13
- 2024Remaining-data-free Machine Unlearning by Suppressing Sample Contributioncited by 13
- 2024Towards Natural Machine Unlearningcited by 11
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- 2026UnlearningSoup: Is Repeated Tuning Necessary for Large Language Model Unlearning?29 Sep 2026
- 2026Correlation-Guided Fast Machine Unlearning via Hessian Analysis11 Sep 2026
- 2026Robust Industrial Cyber Physical Classification Using Neuromorphic Temporal Embeddings and Hybrid SNN XGBoost Under Machine Unlearning Attacks9 Sep 2026
- 2026Cross-Domain Generalization in Machine Unlearning via Label-Conditioned Energy Magnitude Regularization18 Aug 2026
- 2026Similarity-Aware Machine Unlearning31 Jul 2026
- 2026LLM Unlearning for Cyber Defense: A Survey on Methods, Challenges, and Emerging Threats23 Jun 2026
- 2026Erased, but Not Gone: Output Forgetting Is Not True Forgetting23 Jun 2026
- 2026Selective Capability Unlearning in End-to-End Spoken Language Understanding23 Jun 2026
- 2026Machine Unlearning for the XGBoost Model with Network Intrusion Datasets17 Jun 2026
- 2026SUPREME: A Multi-GPU Framework for Reproducible Image Unlearning Method Evaluation29 May 2026
- 2026Distinguishable Deletion: Unifying Knowledge Erasure and Refusal for Large Language Model Unlearning16 May 2026
- 2026DurableUn: Quantization-Induced Recovery Attacks in Machine Unlearning4 May 2026
12 newest of 63 All 63 (JSON)
- 2025ForgetMe: Evaluating Selective Forgetting in Generative Modelscited by 11
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- 2026Forget Many, Forget Right: Scalable and Precise Concept Unlearning in Diffusion Modelscited by 4
- 2026Forget-It-All: Multi-Concept Machine Unlearning via Concept-Aware Neuron Maskingcited by 1
- 2026Forget-It-All: Multi-Concept Machine Unlearning via Concept-Aware Neuron Masking7 Jan 2026
- 2026Forget Many, Forget Right: Scalable and Precise Concept Unlearning in Diffusion Models6 Jan 2026
- 2025ForgetMe: Evaluating Selective Forgetting in Generative Models17 Apr 2025
- 2024Moderating the Generalization of Score-based Generative Model10 Dec 2024
- 2025Approximate Domain Unlearning for Vision-Language Modelscited by 6
- 2025Approximate Domain Unlearning for Vision-Language Models9 Oct 2025
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- 2025Practical Continual Forgetting for Pre-trained Vision Modelscited by 4
- 2025Machine Learners Should Acknowledge the Legal Implications of Large Language Models as Personal Datacited by 4
- 2024Eternal Sunshine of the Mechanical Mind: The Irreconcilability of Machine Learning and the Right to be Forgottencited by 2
- 2024The Approximate Fisher Influence Function: Faster Estimation of Data Influence in Statistical Modelscited by 2
- 2024Uncertainty Quantification of Data Shapley via Statistical Inferencecited by 2
- 2024GraphMU: Repairing Robustness of Graph Neural Networks via Machine Unlearningcited by 1
- 2025A Framework for Cryptographic Verifiability of End-to-End AI Pipelinescited by 1
- 2025Invisible Watermarks, Visible Gains: Steering Machine Unlearning with Bi-Level Watermarking Designcited by 1
- 2026Computational Compliance for AI Regulation: Blueprint for a New Research Domaincited by 1
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- 2026Toward a Benchmark for Controllable Simulation of Imperfect Students with Large Language Models25 May 2026
- 2026Understanding U.S. Users' Security and Privacy Transparency Needs for Consumer-Facing Generative AI19 Apr 2026
- 2026Computational Compliance for AI Regulation: Blueprint for a New Research Domain8 Jan 2026
- 2025MRD-LiNet: A Novel Lightweight Hybrid CNN with Gradient-Guided Unlearning for Improved Drought Stress Identification8 Sep 2025
- 2025A Scenario-Oriented Survey of Federated Recommender Systems: Techniques, Challenges, and Future Directions27 Aug 2025
- 2025Invisible Watermarks, Visible Gains: Steering Machine Unlearning with Bi-Level Watermarking Design13 Aug 2025
- 2025A Framework for Cryptographic Verifiability of End-to-End AI Pipelines28 Mar 2025
- 2025Machine Learners Should Acknowledge the Legal Implications of Large Language Models as Personal Data3 Mar 2025
- 2025Practical Continual Forgetting for Pre-trained Vision Models16 Jan 2025
- 2024Uncertainty Quantification of Data Shapley via Statistical Inference28 Jul 2024
- 2024The Approximate Fisher Influence Function: Faster Estimation of Data Influence in Statistical Models11 Jul 2024
12 newest of 15 All 15 (JSON)