ResearchResearch paperSafety & Alignment · Large Language Models · Training & Scaling1 source · Oct 19, 2026

Safety Offset Learning: When Benign Fine-Tuning Misaligns LLMs

Safety risks from fine-tuning are commonly characterized by the harmfulness of the training data:harmful fine-tuning is considered dangerous, while benign fine-tuning is often assumed to preservealignment.

Key points

  • Harmful fine-tuning and safety-degrading benign fine-tuning can both be understoodas learning the same refusal-to-compliance transition, but on different data distributions.
  • We constructbenign examples that an aligned model initially tends to refuse and pair them with their originalharmless responses, creating a discrepancy between the model's initial refusal and the supervisedanswer.
  • Building on thisobservation, we introduce SAFEOFF, a dataset of benign instructions rewritten to raise the alignedmodel's refusal likelihood and paired with their original answers.
  • Across three aligned LLMs and threesafety benchmarks, SAFEOFF substantially weakens safety alignment despite containing no explicitharmful supervision, suggesting that fine-tuning safety depends not only on what data a model sees, butalso on which behavioral boundary the supervision moves.

Sources (1)

  • [1]Safety Offset Learning: When Benign Fine-Tuning Misaligns LLMs
    arXiv (AI, ML, NLP, CV, robotics, multi-agent) · Oct 19, 12:31 AM
    Safety risks from fine-tuning are commonly characterized by the harmfulness of the training data:harmful fine-tuning is considered dangerous, while benign fine-tuning is often assumed to preservealignment.
    Harmful fine-tuning and safety-degrading benign fine-tuning can both be understoodas learning the same refusal-to-compliance transition, but on different data distributions.

Extractive summary: sentences quoted from the sources.

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