The OWASP Top 10 for Agentic Applications dropped in 2026, and it's a wake-up call. 48% of cybersecurity professionals now rank agentic AI as the #1 attack vector — above ransomware.
Here's what you need to know and how to defend against each risk.
Why Agentic AI Security Is Different
Traditional LLM security assumes a human in the loop. Agentic AI doesn't work that way — agents plan, call tools, store memory, and execute without human review at each step.
The attack surface includes every tool call, every memory read/write, every inter-agent handoff.
The Top 10 Risks
ASI01: Agent Goal Hijacking (Critical)
An attacker embeds instructions in data the agent processes (emails, documents, web content).
Defense:
const CONSTITUTION = [
/ignore\s+(previous|above|all)\s+(instructions|prompts)/i,
/you\s+are\s+now\s+(a|DAN|jailbroken)/i,
/system\s*prompt|reveal.*instructions/i,
];
ASI02: Tool Misuse
Agents generating and executing unsafe code.
Defense: Sandbox all code execution. Treat LLM output as hostile.
ASI03: Identity & Privilege Abuse
Agent credentials stolen or escalated.
Defense: Short-lived tokens, OAuth 2.0, isolated agent identities.
ASI04: Memory Poisoning
Malicious data persists in agent memory, corrupting future decisions.
Defense: TTL on memory entries, structured fact validation.
const FACT_TTL = 3600000; // 1 hour
function cleanExpiredFacts() {
for (const [k, ts] of Object.entries(factTimestamps)) {
if (Date.now() - ts > FACT_TTL) delete facts[k];
}
}
ASI05-ASI10: Brief Overview
- ASI05: Data Exfiltration — scan outputs for secrets
- ASI06: Supply Chain — verify MCP servers
- ASI07: Insecure Inter-Agent Comm — use mTLS
- ASI08: Cascading Failures — circuit breakers + rate limits
- ASI09: Excessive Agency — least-privilege principle
- ASI10: Rogue Agents — anomaly detection + kill switches
Implementation Checklist
- [ ] Constitution rules (20+ patterns)
- [ ] Rate limiting (30 req/min recommended)
- [ ] Memory TTL (1 hour for untrusted facts)
- [ ] Input size validation (4KB max)
- [ ] Output scanning (no secrets/PII in responses)
- [ ] Auth on all mutation endpoints
- [ ] Bind services to 127.0.0.1 unless needed externally
- [ ] Audit logging (JSONL, append-only)
Key Takeaway
Implementation requires 80% governance, 20% technology.
The attacks are real. The defenses are implementable. Start now.
Sources: OWASP GenAI Security Project, Palo Alto Unit 42, CrowdStrike
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