NVIDIA Llama 3.1 Nemotron Ultra 253B v1: LLM Security & Jailbreak Resistance
As of 2026-07-04, NVIDIA Llama 3.1 Nemotron Ultra 253B v1 has an attack success rate (ASR) of 40.0% on Guardion's LLM Vulnerability benchmark — ranking #55 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 Nemotron Ultra 253B v1 compares
Frequently asked questions
How secure is NVIDIA Llama 3.1 Nemotron Ultra 253B v1 against jailbreaks?
NVIDIA Llama 3.1 Nemotron Ultra 253B v1 is weakly resistant — adversarial prompts succeed often without added guardrails. On Guardion's LLM Vulnerability benchmark it records a 40.0% attack success rate (60% robustness), ranking #55 of 93 models (estimated from public safety evaluations).
What is Llama 3.1 Nemotron Ultra 253B v1's attack success rate (ASR)?
Llama 3.1 Nemotron Ultra 253B v1's overall ASR is 40.0% — the share of adversarial prompts that elicit harmful output across zero-shot, TAP, and Crescendo attacks. Lower is safer.
Is Llama 3.1 Nemotron Ultra 253B v1 more secure than Command 2X?
Command 2X is more robust: 39.4% ASR vs Llama 3.1 Nemotron Ultra 253B v1's 40.0%. See the full head-to-head comparison for the per-attack breakdown.
How can I make Llama 3.1 Nemotron Ultra 253B v1 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 Nemotron Ultra 253B v1.
Harden Llama 3.1 Nemotron Ultra 253B v1 in production
Guardion's runtime guardrails block jailbreaks and prompt injection before they reach any model — with sub-130ms policy decisions.
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