TL;DR: Testing 1,000-plus payloads against GPT-5, Gemini 2.5 Flash, Claude Sonnet 4 and Llama 4 Maverick found persistent weakness in prompt injection, input leakage and over-reliance scenarios, according to Pangea. The results show that model resilience varies sharply, and that governance must move beyond generic safety claims to measurable control failure.
Editorial analysis by NHI Mgmt Group, based on content published by Pangea: “Decoding LLM Attack Surfaces: A Deep Dive into Model Vulnerabilities”.
Key questions
Q: What breaks when prompt injection controls are not tested against real attack patterns?
A: When prompt injection controls are not tested against realistic attack patterns, teams often overestimate their guardrails.
Q: Why do LLM prompt injection failures become business risk so quickly?
A: Because the model’s output often feeds real decisions, customer responses or automated actions.
Q: What signs show that an LLM is leaking input or hidden context?
A: Look for the model repeating prompt fragments, reproducing embedded data, or revealing system instructions when asked irrelevant follow-up questions.
Practitioner guidance
- Test prompt boundary integrity before deployment Run adversarial payloads against the full application stack, including system prompts, retrieval layers and any tool output the model can see.
- Restrict context exposure and replay Limit how much history, retrieved data and hidden configuration the model receives in a single task.
- Treat model output as advisory by default Define which outputs may drive customer-facing, financial or operational actions, and require human review or compensating controls where confidence is uncertain or consequences are high.
Bottom line: Prompt injection remains a practical control failure because untrusted input can still override instruction boundaries inside deployed LLM workflows.
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Prompt injection is now a workflow security problem, not just a model robustness problem. Once an LLM sits inside an application, the real failure is often the surrounding trust boundary. Untrusted text, retrieved context and hidden instructions converge in one execution path, so the app architecture determines how far an attacker can steer the model. Practitioners should test the application layer, not only the base model.
A few things that frame the scale:
- AI-related credential leaks surged 81.5% year-over-year in 2025, with the surrounding AI infrastructure leaking 5x faster than core LLM providers, according to the State of Secrets Sprawl 2026.
A question worth separating out:
Q: How should teams compare model safety results across different LLMs?
A: Compare them by failure mode, payload class and test conditions, not by a single overall score. A model that resists unsafe outputs may still fail on input leakage or over-reliance. The useful question is which control boundary fails, how often, and in which deployment pattern.
👉 Read our full editorial: LLM attack testing shows prompt injection still breaks model guardrails