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AI Jailbreak Benchmark Leaderboard: 2026 Results

Compare AI jailbreak benchmark results from FAR.AI, JailbreakBench, HarmBench, StrongREJECT, and MLCommons by scope, judge quality, and procurement value.

By AI Sec Bench Editorial · · 5 min read

The AI jailbreak benchmark leaderboard landscape does not produce one defensible procurement winner. For a named snapshot of frontier-model safeguards, start with FAR.AI; for a repeatable CI release gate, run JailbreakBench or HarmBench against the complete application and use StrongREJECT as a second judge. MLCommons is a useful independent cross-check, but its current public results are de-identified. A high rank should qualify a model for application-specific testing, not approve it for production.

AI jailbreak benchmark leaderboard: current results

As of September 6, 2026, the clearest narrowly scoped, named comparison is FAR.AI’s study of four flagship systems. Its metric is the estimated cost of discovering a universal jailbreak, defined as one prompt template that elicits operationally compliant responses for more than three-quarters of a domain’s harmful goals. The study used 360 goals across CBRNE and offensive-cyber domains and a taxonomy of 67 static techniques (FAR.AI technical report).

Rank within FAR.AI’s studySystemRandom-search resultProcurement interpretation
1=Claude Fable 5No universal jailbreak foundRight-censored result, not proof of resistance to every attack
1=GPT-5.6 SolNo universal jailbreak foundSame limitation: the search ended without a qualifying result
3Gemini 3.1 Pro18 universal jailbreaks; roughly $278 average discovery costStronger than the fourth-ranked system under this harness
4Grok 4.563 universal jailbreaks; roughly $58 average discovery costLowest discovery cost and most random-search findings in this test

This table is not a universal safety order. It covers four products, selected high-harm domains, and one compositional attack methodology. By contrast, MLCommons tested 39 text systems and found that none earned a jailbreak-resistance grade above “Good,” but de-identified every system in the v0.5 results. That supports a market-level conclusion, not a named vendor decision.

What it does: capabilities matrix

These are build-time evaluation resources, not runtime filters. “Output scanning” below means offline grading of a model response; it does not mean the suite can be inserted as a production content-safety classifier.

ResourceInput scanningOutput scanning / jailbreak detectionPII redaction, hallucination check, RAG isolationAudit logging / on-prem vs SaaS / language
FAR.AI LeaderboardNo; composes offline attack promptsThree-stage evaluation of attack successNoneNo runtime log; hosted research leaderboard, not a SaaS control; English study
JailbreakBenchNo; evaluates submitted attacks and defensesLlama-based jailbreak and refusal judgesNoneSaved run metadata and artifacts; open-source local harness plus hosted leaderboard; English corpus
HarmBenchNo; generates red-team test casesBehavior-conditioned classifiers for text, contextual, and multimodal outputsNoneLocal result files; open-source local pipeline; corpus-defined coverage
StrongREJECTNo; applies jailbreak transformations offlineRubric-based or fine-tuned judge scores refusal, specificity, and harmful usefulnessNo generic factuality or RAG checkLocal result data; open-source local package; six harmful-content categories
MLCommons AILuminateNo; applies template and encoding attacksCommon evaluator compares baseline safety with under-attack safetyNoneHosted de-identified results plus local tooling; v0.5 is en-US and covers text and limited text-plus-image

The missing columns matter. None of these resources is a PII redactor, secret scanner, output validator, retrieval-poisoning detector, or agent sandbox. They measure a control objective; they are not the control.

Where it fits

The benchmark should exercise the same path that will ship:

CI attack corpus -> input runtime filter -> system prompt + model + RAG context
                 -> tool allowlist / agent sandbox -> output validator
                 -> benchmark judge -> score, artifacts, human review -> release gate

The production path stops at the user after the output validator. The benchmark path forks responses to an offline judge and retains enough metadata to reproduce the run: model and guardrail versions, system prompt, decoding settings, retrieved context, tool policy, and judge version. Testing only the base model omits the semantic firewall, RAG isolation, and output controls that can change the application result.

Trade-offs that change the ranking

Judge error and false positives. StrongREJECT’s paper reports a Spearman rank correlation of 0.900 for its fine-tuned evaluator and 0.846 for its rubric evaluator against human judgments; their all-response mean absolute errors were 0.084 and 0.077, respectively. Those are evaluator-agreement results on the study dataset, not a production guardrail’s false-positive rate. A procurement bake-off still needs a benign, policy-boundary set and separate false-refusal reporting.

Latency and throughput. These suites run offline, so they add no production p95 latency unless an evaluator is repurposed as a runtime filter. The public leaderboard scores do not provide production p95 or throughput cost. FAR.AI’s cost-to-jailbreak estimates attacker discovery spend, not per-request inference cost. Runtime candidates should be load-tested at the expected context length and concurrency.

Integration effort. JailbreakBench is the lighter choice for reproducing an attack/defense leaderboard with archived artifacts. HarmBench offers a broader red-teaming pipeline, but model adapters, GPUs for local attacks or judges, and policy mapping add operational work. StrongREJECT is most useful as an evaluator cross-check because it penalizes vacuous or incoherent “successful” responses rather than treating non-refusal alone as success.

Residual risk. Jailbreak testing covers part of OWASP LLM01:2025 Prompt Injection. It does not establish resistance to indirect injection through retrieved documents, sensitive-information disclosure, improper output handling, excessive agency, or vector and embedding weaknesses. Pair the leaderboard with RAG poisoning tests, tool allowlists, JSON-schema enforcement, and incident monitoring. This follows the NIST AI RMF Measure function, which calls for documented, repeatable evaluation under conditions similar to deployment.

Who should pick which benchmark

Who should use them: frontier-model procurement teams can use FAR.AI to narrow a shortlist; AppSec and MLOps teams can combine JailbreakBench or HarmBench with StrongREJECT in CI; governance teams can use MLCommons’ baseline-versus-attack framing for repeatable evidence. The attack families behind these tests are catalogued at aisec.blog.

Who should not rely on them alone: RAG or agent owners facing indirect prompt injection, multilingual applications outside the released corpora, and buyers comparing production guardrails on false-positive rate or p95 latency. Those teams need application-shaped tests and runtime-control evidence; guardml.io covers the defensive guardrail layer separately.

Sources

  1. FAR.AI AI Security Leaderboard technical report
  2. JailbreakBench: An Open Robustness Benchmark for Jailbreaking Large Language Models
  3. HarmBench: A Standardized Evaluation Framework for Automated Red Teaming and Robust Refusal
  4. A StrongREJECT for Empty Jailbreaks
  5. MLCommons AILuminate Jailbreak T2T Benchmark v0.5
  6. OWASP LLM01:2025 Prompt Injection
  7. NIST AI RMF Core: Measure
#ai-jailbreak #benchmark #leaderboard #llm-security #model-evaluation
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