Indonesian Journal of Electrical Engineering and Computer Science
Vol 42, No 1: April 2026

ViHateT5 with LoRA: efficient vietnamese toxic news classification on social media

Tran Duc Duong (Posts and Telecommunications Institute of Technology)
Hai Hoan Do (Posts and Telecommunications Institute of Technology)



Article Info

Publish Date
01 Apr 2026

Abstract

We propose an efficient transformer-based approach to detect toxic or misleading news in Vietnamese social media. Motivated by the societal harm of viral misinformation in Vietnam, we fine-tune a Vietnamese T5 model (ViHateT5) on a new dataset of 2,962 social-media news snippets labeled as toxic vs. non-toxic. We use low-rank adaptation (LoRA) to inject trainable layers into ViHateT5, allowing high accuracy with minimal additional parameters. Our model achieves 97.5% macro-F1 on a held-out test set, significantly higher than a PhoBERT baseline by 2.7 points. By focusing on Vietnamese data and a parameter-efficient method, we demonstrate a practical pipeline for low-resource fake-news detection. These results suggest that transformer pretraining on social-media text can effectively capture the subtle cues of deceptive or defamatory news. Limitations: the current model is trained on a specific labeled dataset and may not generalize to all domains; future work should evaluate its fairness and biases in deployment.

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