Cybench
40 professional capture-the-flag tasks from four competitions. Agent must recover the flag, with optional subtasks.
40 professional CTF tasks from four competitions, each split into subtasks for partial credit. Agents work in a Kali Linux environment. The board mixes HAL leaderboard runs with lab system-card scores on 35 to 39 task subsets. Anthropic reports it near saturation. The makers point readers to their later BountyBench.
- Made by
- Stanford
- Released
- August 2024
- Kind
- Capture-the-flag challenges
- Level
- Expert
- Scored
- Checked automatically
- Answers
- Agent task
- Tasks
- All public
- Strongest model tested
- Claude Opus 4.7 #30 on the capability index
- Last in a launch post
- March 2026, dropped after it saturated
- Last model added
- July 2026
- Scores refreshed
- November 12th, 2026
In the authors’ words
Language Model (LM) agents for cybersecurity that are capable of autonomously identifying vulnerabilities and executing exploits have potential to cause real-world impact. Policymakers, model providers, and researchers in the AI and cybersecurity communities are interested in quantifying the capabilities of such agents to help mitigate cyberrisk and investigate opportunities for penetration testing. Toward that end, we introduce Cybench, a framework for specifying cybersecurity tasks and evaluating agents on those tasks. We include 40 professional-level Capture the Flag (CTF) tasks from 4 distinct CTF competitions, chosen to be recent, meaningful, and spanning a wide range of difficulties. Each task includes its own description, starter files, and is initialized in an environment where an agent can execute commands and observe outputs. Since many tasks are beyond the capabilities of existing LM agents, we introduce subtasks for each task, which break down a task into intermediary steps for a more detailed evaluation. To evaluate agent capabilities, we construct a cybersecurity agent and evaluate 8 models: GPT-4o, OpenAI o1-preview, Claude 3 Opus, Claude 3.5 Sonnet, Mixtral 8x22b Instruct, Gemini 1.5 Pro, Llama 3 70B Chat, and Llama 3.1 405B Instruct. For the top performing models (GPT-4o and Claude 3.5 Sonnet), we further investigate performance across 4 agent scaffolds (structed bash, action-only, pseudoterminal, and web search). Without subtask guidance, agents leveraging Claude 3.5 Sonnet, GPT-4o, OpenAI o1-preview, and Claude 3 Opus successfully solved complete tasks that took human teams up to 11 minutes to solve. In comparison, the most difficult task took human teams 24 hours and 54 minutes to solve. All code and data are publicly available at https://cybench.github.io.
Muse Spark leads with 65.4% among models released by April 2026
Best score per model from the benchmark's own leaderboard, read on November 12th, 2026. Where a model ran with several settings or harnesses, we keep its best.
Claude Mythos Preview leads with 100%, claims included
Best score per model from every source, including labs’ own numbers and claims Epoch AI collected from reports and papers. Labs pick their own settings, so a claim can beat an independent run of the same model.
The newest model with a score here came out in April 2026, and nobody has tested a newer one. Among the 20 highest-ranked models on the capability index, these have no score yet:
- Claude Fable 5.2
-
Gemini 4 Carbon
- GPT-6 Astra
- Claude Opus 5.5
- and 16 more
- 1
Muse Spark 65.4%
- 2 Grok 4 43%
- 3 Grok 4.1 39%
- 4 Grok 4 Fast 30%
- 5 o3-mini 22.5%
- 6 Claude 3.7 Sonnet 20%
- 7 Claude 3.5 Sonnet 17.5%
- 8 GPT-4.5 17.5%
- 9 GPT-4o May 2024 12.5%
- 10 Claude 3 Opus 10%
- 11 o1-mini 10%
- 12 o1-preview 10%
- 13
Mixtral 8x22B 7.50%
- 14
Gemini 1.5 Pro May 2024 7.50%
- 15
Llama 3.1-405B 7.50%
- 16
Llama 3-70B 5.00%
Source: Official Cybench leaderboard
- 100.0 Claude Mythos Preview
- 96.0 Claude Opus 4.7
- 93.0 Claude Opus 4.6
- 92.9
Muse Spark 1.1
- 90.0 Claude Sonnet 4.6
- 82.0 Claude Opus 4.5
- 65.4
Muse Spark
- 60.0 Claude Sonnet 4.5
- 56.4 Claude Opus 4
- 56.4 Claude Sonnet 4
- 53.0 Grok 4.20
- 51.4 Claude Opus 4.1
- 46.9 Claude Haiku 4.5
- 44.1 Claude 3.7 Sonnet
- 43.0 Grok 4
- 39.0 Grok 4.1
- 30.0 Grok 4 Fast
- 25.0
Code World Model (CWM)
- 22.5 o3-mini
- 22.5 grok-code-fast-1
- 17.5 Claude 3.5 Sonnet
- 17.5 GPT-4.5
- 12.5 GPT-4o
- 10.0 Claude 3 Opus
- 10.0 o1-mini
- 10.0 o1-preview
- 7.50
Mixtral 8x22B
- 7.50
Gemini 1.5 Pro
- 7.50
Llama 3.1-405B
- 5.00
Llama 3-70B
- 1 Claude Mythos Preview 100%
- 2 Claude Opus 4.7 96%
- 3 Claude Opus 4.6 93%
- 4
Muse Spark 1.1 92.9%
- 5 Claude Sonnet 4.6 90%
- 6 Claude Opus 4.5 82%
- 7
Muse Spark 65.4%
- 8 Claude Sonnet 4.5 unknown thinking 60%
- 9 Claude Opus 4 56.4%
- 10 Claude Sonnet 4 56.4%
- 11 Grok 4.20 53%
- 12 Claude Opus 4.1 51.4%
- 13 Claude Haiku 4.5 46.9%
- 14 Claude 3.7 Sonnet 44.1%
- 15 Grok 4 43%
- 16 Grok 4.1 39%
- 17 Grok 4 Fast 30%
- 18
Code World Model (CWM) 25%
- 19 o3-mini 22.5%
- 20 grok-code-fast-1 22.5%
- 21 Claude 3.5 Sonnet 17.5%
- 22 GPT-4.5 17.5%
- 23 GPT-4o May 2024 12.5%
- 24 Claude 3 Opus 10%
- 25 o1-mini 10%
- 26 o1-preview 10%
- 27
Mixtral 8x22B 7.50%
- 28
Gemini 1.5 Pro May 2024 7.50%
- 29
Llama 3.1-405B 7.50%
- 30
Llama 3-70B 5.00%
Sources: Labs’ model cards, official Cybench leaderboard and Another board, via Epoch AI (CC BY 4.0)
| # | Model | Score | Setting | Date | Source |
|---|---|---|---|---|---|
| 1 | | 65.4% | Apr 2026 | Official leaderboard | |
| 2 | Grok 4 | 43% | Jul 2025 | Official leaderboard | |
| 3 | Grok 4.1 | 39% | Nov 2025 | Official leaderboard | |
| 4 | Grok 4 Fast | 30% | Sep 2025 | Official leaderboard | |
| 5 | o3-mini | 22.5% | Jan 2025 | Official leaderboard | |
| 6 | Claude 3.7 Sonnet | 20% | Feb 2025 | Official leaderboard | |
| 7 | Claude 3.5 Sonnet | 17.5% | Jun 2024 | Official leaderboard | |
| 8 | GPT-4.5 | 17.5% | Feb 2025 | Official leaderboard | |
| 9 | GPT-4o May 2024 | 12.5% | May 2024 | Official leaderboard | |
| 10 | Claude 3 Opus | 10% | Feb 2024 | Official leaderboard | |
| 11 | o1-mini | 10% | Sep 2024 | Official leaderboard | |
| 12 | o1-preview | 10% | Sep 2024 | Official leaderboard | |
| 13 | | 7.50% | Apr 2024 | Official leaderboard | |
| 14 | | 7.50% | May 2024 | Official leaderboard | |
| 15 | | 7.50% | Jul 2024 | Official leaderboard | |
| 16 | | 5.00% | Apr 2024 | Official leaderboard |
| # | Model | Score | Setting | Date | Source |
|---|---|---|---|---|---|
| 1 | Claude Mythos Preview | 100% | Apr 2026 | Lab model card | |
| 2 | Claude Opus 4.7 | 96% | Apr 2026 | Lab model card | |
| 3 | Claude Opus 4.6 | 93% | Feb 2026 | Lab model card | |
| 4 | | 92.9% | Jul 2026 | Lab model card | |
| 5 | Claude Sonnet 4.6 | 90% | Feb 2026 | Lab model card | |
| 6 | Claude Opus 4.5 | 82% | Nov 2025 | Lab model card | |
| 7 | | 65.4% | Apr 2026 | Official leaderboard | |
| 8 | Claude Sonnet 4.5 | 60% | unknown thinking | Sep 2025 | Claim in Opus 4.5 System Card, via Epoch AI |
| 9 | Claude Opus 4 | 56.4% | May 2025 | Lab model card | |
| 10 | Claude Sonnet 4 | 56.4% | May 2025 | Lab model card | |
| 11 | Grok 4.20 | 53% | Mar 2026 | Lab model card | |
| 12 | Claude Opus 4.1 | 51.4% | Aug 2025 | Lab model card | |
| 13 | Claude Haiku 4.5 | 46.9% | Oct 2025 | Lab model card | |
| 14 | Claude 3.7 Sonnet | 44.1% | Feb 2025 | Lab model card | |
| 15 | Grok 4 | 43% | Jul 2025 | Official leaderboard | |
| 16 | Grok 4.1 | 39% | Nov 2025 | Official leaderboard | |
| 17 | Grok 4 Fast | 30% | Sep 2025 | Official leaderboard | |
| 18 | | 25% | Oct 2025 | Lab model card | |
| 19 | o3-mini | 22.5% | Jan 2025 | Official leaderboard | |
| 20 | grok-code-fast-1 | 22.5% | Aug 2025 | Lab model card | |
| 21 | Claude 3.5 Sonnet | 17.5% | Jun 2024 | Official leaderboard | |
| 22 | GPT-4.5 | 17.5% | Feb 2025 | Official leaderboard | |
| 23 | GPT-4o May 2024 | 12.5% | May 2024 | Official leaderboard | |
| 24 | Claude 3 Opus | 10% | Feb 2024 | Official leaderboard | |
| 25 | o1-mini | 10% | Sep 2024 | Official leaderboard | |
| 26 | o1-preview | 10% | Sep 2024 | Official leaderboard | |
| 27 | | 7.50% | Apr 2024 | Official leaderboard | |
| 28 | | 7.50% | May 2024 | Official leaderboard | |
| 29 | | 7.50% | Jul 2024 | Official leaderboard | |
| 30 | | 5.00% | Apr 2024 | Official leaderboard |
Labs report scores for 18 models in their cards. Epoch AI collected claims for 9 models from labs’ reports and papers. Switch the scores above to rank them together.
4 models have held number one on the official leaderboard since its release in August 2024 8 models have held number one with claims included since its release in August 2024
Lab claims count from the day the card came out, independent runs from the model’s release. We draw one row each for the benchmark’s own leaderboard and what labs claim in their cards.
Sources: Official Cybench leaderboard and labs’ model cards
Anthropic’s own number for Claude Opus 4.6 passed 85% in February 2026
All the scores we have, one dot each, so a model tested at several settings appears more than once.
Sources: Official Cybench leaderboard, labs’ model cards and claims collected by Epoch AI (CC BY 4.0)
Labs headline it less often now, last in March 2026
Launch posts from every lab that has listed it, one tick per post. Tall colored ticks include it, and short gray ones leave it out.
| Date | Launch post | Score | As the post writes it |
|---|---|---|---|
| Mar 9, 2026 | Grok 4.20 | 53 | CyBench, success rate 0.53, unguided, Grok 4.2 SA, Table 4 |
19 system cards report it, from 3 labs
Besides launch posts, we read the system cards, model cards and technical reports labs publish with a release. They report far more, including safety and frontier-risk tests.
| Date | Document | Score | As the document writes it | Section |
|---|---|---|---|---|
| Jul 9, 2026 | | 92.9 | Cybench pass@1, unguided, 40 challenges, unmitigated Muse Spark 1.1 (Table 1, Table 3). pass@10 = 97.0 | Cyber risk |
| Jun 12, 2026 | | 65.4 | CyBench pass@1, all 40 challenges (Table 1, Table 7). pass@10 79.0, pass@30 82.2 | Cyber risk |
| Apr 16, 2026 | Claude Opus 4.7 system card | 96 | Cybench, pass@1 96% on a 35-challenge subset, 10 trials per challenge, no thinking with think tool (3.3.1) | Cyber risk |
| Apr 7, 2026 | Grok 4.20 model card | 53 | CyBench, success rate 0.53, unguided, Grok 4.2 SA, Table 4 | Cyber risk |
| Apr 7, 2026 | Claude Mythos Preview system card | 100 | Cybench, pass@1 100% on a 35-challenge subset, 10 trials per challenge, no thinking with think tool (3.3.1) | Cyber risk |
| Feb 17, 2026 | Claude Sonnet 4.6 system card | 90 | Cybench, average pass@1 0.90 on the RSP subset of 37 challenges; pass@30 100 (6.4.7) | Cyber risk |
| Feb 5, 2026 | Claude Opus 4.6 system card | 93 | Cybench, average pass@1 0.93 on the RSP subset, 3 of 40 not run; 100% with 30 trials (8.4.7, Figure 8.4.7.A) | Cyber risk |
| Nov 24, 2025 | Claude Opus 4.5 system card | 82 | Cybench, average pass@1 0.82 on the subset of challenges used for RSP evaluations, 1 of 40 not run (7.4.7, Figure 7.4.6.A) | Cyber risk |
| Nov 17, 2025 | Grok 4.1 model card | 39 | CyBench, unguided success rate 0.39, Grok 4.1 Thinking (Table 4) | Cyber risk |
| Oct 15, 2025 | Claude Haiku 4.5 system card | 46.9 | Cybench 32-challenge subset, 15/32 solved at least once in 30 attempts, pass@30 (6.4) | Cyber risk |
| Oct 8, 2025 | | 25 | Cybench unguided, pass@10, 10 of 40 CTFs. Easy 50.0, Medium 11.1, Hard 12.5 (Tables 3 and 4) | Cyber risk |
| Sep 29, 2025 | Claude Sonnet 4.5 system card | Cybench, 37 of 40 challenges, mean pass@1 by difficulty and category and pass@k curve, charts without printed values. Text says success above 80% at 30 trials (5.2.2, Figures 5.2.2.A and 5.2.2.B) | Cyber risk | |
| Sep 19, 2025 | Grok 4 Fast model card | 30 | CyBench, unguided success rate 30.0 (Table 3) | Cyber risk |
| Aug 26, 2025 | grok-code-fast-1 model card | 22.5 | CyBench, unguided success rate 22.5 (Table 3) | Cyber risk |
| Aug 20, 2025 | Grok 4 model card | 43 | CyBench, unguided success rate 0.43, Grok 4 API, Inspect harness (Table 3) | Cyber risk |
| Aug 5, 2025 | Claude Opus 4.1 system card addendum | 51.4 | Cybench 35-challenge subset, 18/35 solved, pass@30 (6.5.1) | Cyber risk |
| May 22, 2025 | Claude Sonnet 4 system card | 56.4 | Cybench, 22/39 challenges solved, pass@30 (7.4.7) | Cyber risk |
| May 22, 2025 | Claude Opus 4 system card | 56.4 | Cybench, 22/39 challenges solved, pass@30 (7.4.7) | Cyber risk |
| Feb 24, 2025 | Claude 3.7 Sonnet system card | 44.1 | Cybench, succeeded at least once on 15/34 challenges tested (pass@k over up to 30 trials). Best-of-k curve on a 30-challenge subset has no printed values (7.3.2, Figure 25) | Cyber risk |
5 lab claims next to the leaderboard
Each score a lab reported for its own model, beside the same model's best score on the leaderboard. Gaps mostly come from different harnesses, effort levels and task subsets. 4 of them match, which usually means one side copied the other. Every benchmark.
| Model | Lab says | Board says | Gap | What differs |
|---|---|---|---|---|
| Claude 3.7 Sonnet | 44.1% Cybench, succeeded at least once on 15/34 challenges tested (pass@k over up to 30 trials). Best-of-k curve on a 30-challenge subset has no printed values (7.3.2, Figure 25) | 20% Leaderboard | +24 pts | Anthropic counts challenges solved at least once across up to 30 trials, while the board counts eight solved challenges in its run. |
| Grok 4 | 43% CyBench, unguided success rate 0.43, Grok 4 API, Inspect harness (Table 3) | 43% Leaderboard | Same | |
| Grok 4 Fast | 30% CyBench, unguided success rate 30.0 (Table 3) | 30% Leaderboard | Same | |
| Grok 4.1 | 39% CyBench, unguided success rate 0.39, Grok 4.1 Thinking (Table 4) | 39% Leaderboard | Same | |
| | 65.4% CyBench pass@1, all 40 challenges (Table 1, Table 7). pass@10 79.0, pass@30 82.2 | 65.4% Leaderboard | Same |
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