HarmProfile: Characterizing Harmful Distributions in Frontier LLMs

Zhouyuan Ma, Yutao Wu, Hanxun Huang, Xiang Zheng, Xiao Liu, Yixin Cao, Zuxuan Wu, Xingjun Ma, Yu-Gang Jiang


Abstract
Frontier large language models (LLMs) safety evaluation has largely treated harmful generation as an attack outcome rather than an object of analysis. Consequently, little is known about the outputs themselves, partly because large-scale, high-quality collections of frontier-model misbehavior are difficult to obtain. To address this gap, we introduce **HarmProfile**, a content-centric benchmark dataset that collects model misbehavior across diverse harm categories and model families, and defines the resulting content distribution as a model-level risk profile. The premise is that, just as linguistic behavior can be characterized from an utterance corpus, model risk can be characterized from the content, severity, and variation of its safety failures. HarmProfile contains over 80,000 validated artifacts from 23 frontier LLMs across 13 model families, organized into 15 harm categories and 57 subcategories. Using this corpus, we find that frontier LLMs reliably produces harmful content at scale, yet exhibit distinct risk profiles; both harmfulness and diversity grow with model capability, suggesting that frontier LLMs may appear safe yet harbor increasingly dangerous knowledge beneath the alignment surface. The code and dataset resources are publicly available at https://github.com/fresh-ma/HarmProfile.
Anthology ID:
2026.findings-emnlp.1479
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
31477–31523
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.1479/
DOI:
Bibkey:
Cite (ACL):
Zhouyuan Ma, Yutao Wu, Hanxun Huang, Xiang Zheng, Xiao Liu, Yixin Cao, Zuxuan Wu, Xingjun Ma, and Yu-Gang Jiang. 2026. HarmProfile: Characterizing Harmful Distributions in Frontier LLMs. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 31477–31523, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
HarmProfile: Characterizing Harmful Distributions in Frontier LLMs (Ma et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.1479.pdf