Benchmark Almanac

Cybench

Muse Spark 65.4% leads since April 2026
Claude Mythos Preview 100% leads since April 2026
Fading

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.

Abstract of Cybench: A Framework for Evaluating Cybersecurity Capabilities and Risks of Language Models (arXiv:2408.08926, CC0)
16
Models scored on its own leaderboard
1
Launch post lists it, from 1 lab
19
System cards report it, from 3 labs

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:

  1. 1 Muse Spark 65.4%
  2. 2 Grok 4 43%
  3. 3 Grok 4.1 39%
  4. 4 Grok 4 Fast 30%
  5. 5 o3-mini 22.5%
  6. 6 Claude 3.7 Sonnet 20%
  7. 7 Claude 3.5 Sonnet 17.5%
  8. 8 GPT-4.5 17.5%
  9. 9 GPT-4o May 2024 12.5%
  10. 10 Claude 3 Opus 10%
  11. 11 o1-mini 10%
  12. 12 o1-preview 10%
  13. 13 Mixtral 8x22B 7.50%
  14. 14 Gemini 1.5 Pro May 2024 7.50%
  15. 15 Llama 3.1-405B 7.50%
  16. 16 Llama 3-70B 5.00%

Source: Official Cybench leaderboard

#ModelScoreSettingDateSource
1 Muse Spark 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 Mixtral 8x22B 7.50% Apr 2024 Official leaderboard
14 Gemini 1.5 Pro May 2024 7.50% May 2024 Official leaderboard
15 Llama 3.1-405B 7.50% Jul 2024 Official leaderboard
16 Llama 3-70B 5.00% Apr 2024 Official leaderboard
#ModelScoreSettingDateSource
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 Muse Spark 1.1 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 Muse Spark 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 Code World Model (CWM) 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 Mixtral 8x22B 7.50% Apr 2024 Official leaderboard
28 Gemini 1.5 Pro May 2024 7.50% May 2024 Official leaderboard
29 Llama 3.1-405B 7.50% Jul 2024 Official leaderboard
30 Llama 3-70B 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.

Anthropic OpenAI xAI Meta
Own leaderboard Not tested since Apr 2026
Muse Spark 65.4%
Lab claims Passed 85% in Feb 2026, by Claude Opus 4.6

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.

On the benchmark’s own leaderboard Reported by the lab in its model card A claim Epoch AI collected from a report or paper Best so far
0% 20% 40% 60% 80% 100% 2024 2025 2026 Near the ceiling (85%) Claude Mythos Preview Claude Opus 4.6 Claude Opus 4.5 Claude Sonnet 4.5 Claude 3.7 Sonnet o3-mini Claude 3.5 Sonnet 0% 20% 40% 60% 80% 100% 2024 2025 2026 Near the ceiling (85%) Claude Mythos Preview Claude Opus 4.6

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.

xAI
DateLaunch postScoreAs 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.

DateDocumentScoreAs the document writes itSection
Jul 9, 2026 Muse Spark 1.1 system card 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 Muse Spark system card 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 Code World Model (CWM) technical report 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
Muse Spark 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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