OWASP Top 10 for LLM Applications 2026: The Complete Guide, Category by Category

By Carlos Montiel | Enterprise AI Specialist
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Published: 2026-07-28 | By: Carlos Montiel | Reading time: ~4 minutes

For the first time, the OWASP Top 10 for LLM isn't based solely on what experts believe is dangerous — it's based on 6,639 real incidents. And what climbed fastest in the ranking says a lot about where the risk is actually moving.

A new methodology: real data, not just expert vote

The 2026 edition was built with hundreds of AI security experts, but for the first time community vote (75% of the weight) was combined with data from 6,639 real incidents pulled from public vulnerability databases and an AI harms database (the remaining 25% of the weight) — a methodological shift that anchors the ranking in what's actually happening, not just what seems dangerous in theory.

What stayed on top — and what climbed

Prompt Injection and Sensitive Information Disclosure held the top two spots, unchanged from previous editions. But **Excessive Agency** — the risk of an agent having more authority than it actually needs for its task — jumped from sixth place in 2025 to third in 2026, pushing supply chain and training-data poisoning risks further down. It's the clearest evidence of the shifting focus: the risk is no longer just "the model says something bad," it's "the agent does something bad with real permissions."

The philosophy shift: blast radius, not perfect prevention

The 2026 edition reframes the entire goal: "stop trying to build a model that can't be tricked. Build the system around it, so that when the model is tricked — and it will be — nothing important breaks." It's a significant philosophical shift: instead of chasing perfect prevention (impossible), the focus moves to limiting the blast radius when prevention fails — the same defense-in-depth principle already applied in traditional cybersecurity, now made explicit for LLMs.

How to use this list in practice

The Top 10 isn't a compliance checklist — it's a threat-modeling prioritization guide. For every AI system in production, it's worth explicitly reviewing which controls exist against the top 3-4 risks on the list (prompt injection, sensitive information disclosure, excessive agency) before worrying about the rarer risks at the bottom — that's where most real incidents, according to the 2026 data itself, keep concentrating.

Carlos Montiel
Enterprise AI Solutions Architect
Specialist in LLMs, Agents, and Orchestration
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