Closing the Distribution Gap in Adversarial Training for LLMs

Fuente: arXiv
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Main Authors: Hu, Chengzhi, Dornbusch, Jonas, Lüdke, David, Günnemann, Stephan, Schwinn, Leo
Format: Preprint
Published: 2026
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_version_ 1866911455094243328
author Hu, Chengzhi
Dornbusch, Jonas
Lüdke, David
Günnemann, Stephan
Schwinn, Leo
author_facet Hu, Chengzhi
Dornbusch, Jonas
Lüdke, David
Günnemann, Stephan
Schwinn, Leo
contents Adversarial training for LLMs is one of the most promising methods to reliably improve robustness against adversaries. However, despite significant progress, models remain vulnerable to simple in-distribution exploits, such as rewriting prompts in the past tense or translating them into other languages. We argue that this persistent fragility stems from a fundamental limitation in current adversarial training algorithms: they minimize adversarial loss on their training set but inadequately cover the data distribution, resulting in vulnerability to seemingly simple attacks. To bridge this gap, we propose Distributional Adversarial Training, DAT. We leverage Diffusion LLMs to approximate the true joint distribution of prompts and responses, enabling generation of diverse, high-likelihood samples that address generalization failures. By combining optimization over the data distribution provided by the diffusion model with continuous adversarial training, DAT achieves substantially higher adversarial robustness than previous methods.
format Preprint
id arxiv_https___arxiv_org_abs_2602_15238
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Closing the Distribution Gap in Adversarial Training for LLMs
Hu, Chengzhi
Dornbusch, Jonas
Lüdke, David
Günnemann, Stephan
Schwinn, Leo
Machine Learning
Artificial Intelligence
Cryptography and Security
I.2.6; K.6.5
Adversarial training for LLMs is one of the most promising methods to reliably improve robustness against adversaries. However, despite significant progress, models remain vulnerable to simple in-distribution exploits, such as rewriting prompts in the past tense or translating them into other languages. We argue that this persistent fragility stems from a fundamental limitation in current adversarial training algorithms: they minimize adversarial loss on their training set but inadequately cover the data distribution, resulting in vulnerability to seemingly simple attacks. To bridge this gap, we propose Distributional Adversarial Training, DAT. We leverage Diffusion LLMs to approximate the true joint distribution of prompts and responses, enabling generation of diverse, high-likelihood samples that address generalization failures. By combining optimization over the data distribution provided by the diffusion model with continuous adversarial training, DAT achieves substantially higher adversarial robustness than previous methods.
title Closing the Distribution Gap in Adversarial Training for LLMs
topic Machine Learning
Artificial Intelligence
Cryptography and Security
I.2.6; K.6.5
url https://arxiv.org/abs/2602.15238