TL;DR: LLM deployments now face prompt injection, sensitive data leakage, supply chain compromise, output misuse and excessive agency, with Akto mapping those risks across the OWASP Top 10 for LLM applications, NIST AI governance and the EU AI Act. The practical issue is no longer model quality alone but whether access, outputs and tool use are governed tightly enough to survive adversarial use.
Editorial analysis by NHI Mgmt Group, based on content published by Akto: “LLM Security Risks: The Biggest Threats to Large Language Models in 2026”.
Key questions
Q: What breaks when LLMs can act on prompts and connected tools without tight authorization?
A: The boundary between conversation and execution breaks.
Q: Why do prompt injection attacks create governance risk for AI agents?
A: Prompt injection creates governance risk because the model often sits in the control path between text input and tool execution.
Q: What are the signs that LLM output controls are failing in production?
A: Common warning signs include repeated policy bypasses, user prompts that trigger disallowed content, unexpected data exposure in responses, and high rates of blocked or rewritten outputs.
Practitioner guidance
- Map every LLM trust boundary Document where prompts, retrieved content, tool calls, and output handling cross from one trust domain to another.
- Restrict agent permissions by task Give each model or agent only the specific tool scopes, data sources, and workflow rights required for the current use case.
- Validate outputs before execution Block any workflow that feeds model output directly into databases, web pages, refunds, or ticketing systems without inspection.
Bottom line: LLM security risk in 2026 is about how models are trusted to process, retrieve, and act, not only about how well they generate text.
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Prompt injection is now a governance problem, not just an LLM safety problem. The core failure is the collapse of the boundary between content and instruction. Once retrieved text can steer workflow or tool choice, traditional content moderation no longer protects the environment. Practitioners need to treat untrusted input as a control-plane threat, not only a data-plane issue.
A few things that frame the scale:
- Half of companies using generative AI will deploy agentic AI by 2027, according to Deloitte's 2025 Technology Predictions.
A question worth separating out:
Q: How should teams govern AI agents that use MCP?
A: Treat each connected agent as a non-human identity with an owner, a scope, and a review cycle. The practical control set is familiar: least privilege, secret rotation, access expiration, and auditability across the systems the agent can reach.
👉 Read our full editorial: LLM security risks in 2026: prompt injection, MCP and agent abuse