benchmark 2026

PIArena: A Platform for Prompt Injection Evaluation

Runpeng Geng , Chenlong Yin , Yanting Wang , Ying Chen , Jinyuan Jia

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Published on arXiv

2604.08499

Prompt Injection

OWASP LLM Top 10 — LLM01

Key Finding

Reveals that state-of-the-art defenses show limited generalizability across tasks and are vulnerable to adaptive attacks, especially when injected tasks align with target tasks

PIArena

Novel technique introduced


Prompt injection attacks pose serious security risks across a wide range of real-world applications. While receiving increasing attention, the community faces a critical gap: the lack of a unified platform for prompt injection evaluation. This makes it challenging to reliably compare defenses, understand their true robustness under diverse attacks, or assess how well they generalize across tasks and benchmarks. For instance, many defenses initially reported as effective were later found to exhibit limited robustness on diverse datasets and attacks. To bridge this gap, we introduce PIArena, a unified and extensible platform for prompt injection evaluation that enables users to easily integrate state-of-the-art attacks and defenses and evaluate them across a variety of existing and new benchmarks. We also design a dynamic strategy-based attack that adaptively optimizes injected prompts based on defense feedback. Through comprehensive evaluation using PIArena, we uncover critical limitations of state-of-the-art defenses: limited generalizability across tasks, vulnerability to adaptive attacks, and fundamental challenges when an injected task aligns with the target task. The code and datasets are available at https://github.com/sleeepeer/PIArena.


Key Contributions

  • First unified platform (PIArena) for standardized prompt injection evaluation across attacks, defenses, and benchmarks
  • Dynamic strategy-based adaptive attack that optimizes injected prompts based on defense feedback
  • Comprehensive evaluation revealing limited generalizability and vulnerability to adaptive attacks in SOTA defenses

🛡️ Threat Analysis


Details

Domains
nlp
Model Types
llm
Threat Tags
black_boxinference_time
Datasets
Multiple existing prompt injection benchmarks (unified in platform)
Applications
llm security evaluationprompt injection testing