CREST: Universal Safety Guardrails through Cluster-Guided Cross-Lingual Transfer

Lavish Bansal, Naman Mishra


Abstract
Ensuring content safety in large language models (LLMs) is essential for their deployment in real-world applications. However, existing safety guardrails are predominantly tailored for high-resource languages, leaving a significant portion of the world’s population underrepresented who communicate in low-resource languages. To address this, we introduce CREST (CRoss-lingual Efficient Safety Transfer), a parameter-efficient multilingual safety classification model that supports 100 languages with only 0.5B parameters. By training on a strategically chosen subset of only 13 high-resource languages, our model utilizes cluster-based cross-lingual transfer from a few to 100 languages, enabling effective generalization to both unseen high-resource and low-resource languages. This approach addresses the challenge of limited training data in low-resource settings. We conduct comprehensive evaluations across six safety benchmarks to demonstrate that CREST outperforms existing state-of-the-art guardrails of comparable scale and achieves competitive results against models with significantly larger parameter counts (≥ 2.5B parameters). Our findings highlight the limitations of language-specific guardrails and underscore the importance of developing universal, language-agnostic safety systems that can scale effectively to serve global populations.
Anthology ID:
2026.lrec-1.701
Volume:
Proceedings of the Fifteenth Language Resources and Evaluation Conference
Month:
May
Year:
2026
Address:
Palma de Mallorca, Spain
Editors:
Stelios Piperidis, Núria Bel, Henk van den Heuvel, Nancy Ide, Simon Krek, Antonio Toral
Venue:
LREC
SIG:
Publisher:
ELRA Language Resource Association
Note:
Pages:
8908–8922
Language:
External URL:
https://lrec.elra.info/lrec2026-main-701
DOI:
10.63317/253ofxgdtz24
Bibkey:
Cite (ACL):
Lavish Bansal and Naman Mishra. 2026. CREST: Universal Safety Guardrails through Cluster-Guided Cross-Lingual Transfer. In Proceedings of the Fifteenth Language Resources and Evaluation Conference, pages 8908–8922, Palma de Mallorca, Spain. ELRA Language Resource Association.
Cite (Informal):
CREST: Universal Safety Guardrails through Cluster-Guided Cross-Lingual Transfer (Bansal & Mishra, LREC 2026)
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