Graph-Guided Selective Unlearning for Language Models: Controlling Support Routes Beyond Forget Seeds

Waqas Khan, Tabinda Sarwar, Jingyue Cong, Xun Yi, Estrid He


Abstract
Enterprises fine-tune language models on proprietary data that may later require removal due to privacy, contractual, or compliance obligations. Selective unlearning removes requested knowledge while preserving model utility, offering a practical alternative to full retraining, but existing methods treat the explicitly identified forget examples as the complete deletion scope. This is insufficient when target knowledge remains recoverable through paraphrases, aliases, or neighboring training examples. We propose GraphSU, a graph-guided controller that expands the deletion scope beyond forget seeds by constructing a weighted support-route graph, propagating deletion pressure through it, and applying graded forgetting strengths to high-risk neighbors. On TOFU and PISTOL with GPT-2 Medium and Llama-3.2-3B-Instruct, GraphSU achieves the lowest utility-feasible soft leakage across all deletion settings, reducing leakage by up to 49.5 percentage points over a matched seed-only baseline, demonstrating that effective enterprise unlearning requires controlling support routes, not just forget seeds.
Anthology ID:
2026.emnlp-industry.261
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing: Industry Track
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Pepa Atanasova, Gholamreza Haffari, Minghan Wang
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
4398–4414
Language:
URL:
https://aclanthology.org/2026.emnlp-industry.261/
DOI:
Bibkey:
Cite (ACL):
Waqas Khan, Tabinda Sarwar, Jingyue Cong, Xun Yi, and Estrid He. 2026. Graph-Guided Selective Unlearning for Language Models: Controlling Support Routes Beyond Forget Seeds. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing: Industry Track, pages 4398–4414, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Graph-Guided Selective Unlearning for Language Models: Controlling Support Routes Beyond Forget Seeds (Khan et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-industry.261.pdf