Meta Llama 3.1 405B Instruct: LLM Security & Jailbreak Resistance
As of 2026-07-04, Meta Llama 3.1 405B Instruct has an attack success rate (ASR) of 36.0% on Guardion's LLM Vulnerability benchmark — ranking #46 of 93 models. It is weakly resistant — adversarial prompts succeed often without added guardrails.
Attack Success Rate (ASR) is the share of adversarial prompts that elicit harmful output across zero-shot, TAP, and Crescendo attacks (HarmBench framework). Lower is safer. "Est." models are calibrated from public safety evaluations pending a Guardion benchmark run.
How Llama 3.1 405B Instruct compares
Frequently asked questions
How secure is Meta Llama 3.1 405B Instruct against jailbreaks?
Meta Llama 3.1 405B Instruct is weakly resistant — adversarial prompts succeed often without added guardrails. On Guardion's LLM Vulnerability benchmark it records a 36.0% attack success rate (64% robustness), ranking #46 of 93 models (estimated from public safety evaluations).
What is Llama 3.1 405B Instruct's attack success rate (ASR)?
Llama 3.1 405B Instruct's overall ASR is 36.0% — the share of adversarial prompts that elicit harmful output across zero-shot, TAP, and Crescendo attacks. Lower is safer.
Is Llama 3.1 405B Instruct more secure than Llama 4 Behemoth?
Llama 4 Behemoth is more robust: 25.0% ASR vs Llama 3.1 405B Instruct's 36.0%. See the full head-to-head comparison for the per-attack breakdown.
How can I make Llama 3.1 405B Instruct safer to deploy?
Even robust models are bypassed under sustained attack. An inline runtime guardrail that classifies prompts and responses — like Guardion's prompt-defense models — blocks jailbreaks and prompt injection before they reach Llama 3.1 405B Instruct.
Harden Llama 3.1 405B Instruct in production
Guardion's runtime guardrails block jailbreaks and prompt injection before they reach any model — with sub-130ms policy decisions.
Request a demo