Benchmark Almanac

Sandbox Bench

GPT-6 Astra 45.5% leads since September 2026
Only in system cards

Agents find and exploit vulnerabilities in runtimes, file format parsers and egress proxies across 22 challenges. Success means recovering the protected flag.

In-house OpenAI evaluation. Most targets are undisclosed zero days.

Made by
OpenAI
Released
September 2026
Kind
Finding and exploiting real bugs
Level
Research frontier
Scored
Checked automatically
Answers
Agent task
Tasks
Kept private
Strongest model tested
GPT-6 Astra #3 on the capability index
Last in a system card
October 2026
Last model added
October 2026
4
Models scored in lab cards
4
System cards report it, from 1 lab

GPT-6 Astra leads with 45.5%

Best score per model as labs report them in their own cards. Labs pick their own settings, so these compare less cleanly than independent runs.

  1. 45.5 GPT-6 Astra
  2. 22.7 GPT-6.1 Terra
  3. 4.50 GPT-6 Luna
  4. 4.50 GPT-6 Sol
  1. 1 GPT-6 Astra 45.5%
  2. 2 GPT-6.1 Terra 22.7%
  3. 3 GPT-6 Luna 4.50%
  4. 4 GPT-6 Sol 4.50%

Source: Labs’ model cards

#ModelScoreSettingDateSource
1 GPT-6 Astra 45.5% Sep 2026 Lab model card
2 GPT-6.1 Terra 22.7% Oct 2026 Lab model card
3 GPT-6 Luna 4.50% Sep 2026 Lab model card
4 GPT-6 Sol 4.50% Sep 2026 Lab model card

Number one over time

Lab claims count from the day the card came out, independent runs from the model’s release.

OpenAI
Lab claims 1 leader
GPT-6 Astra 45.5%

Source: Labs’ model cards

Scores over time

All the scores we have, one dot each, so a model tested at several settings appears more than once.

Reported by the lab in its model card
0% 20% 40% 60% 80% 100% 2027 Near the ceiling (85%) GPT-6 Astra 0% 20% 40% 60% 80% 100% 2027 Near the ceiling (85%) GPT-6 Astra

Source: Labs’ model cards

Labs report it only in system cards

We read the headline results of 522 launch posts from 52 labs, and none of them list this benchmark. Some system cards do, below.

4 system cards report it, from 1 lab

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
Oct 26, 2026 GPT-6.1 Terra system card addendum 22.7 Sandbox Bench, 5 of 22 targets succeeded (Figure 28, 9.0.2.3) Cyber risk
Sep 22, 2026 GPT-6 Sol system card 4.5 Sandbox Bench, 1 of 22 targets (A.8.1.2.3) Cyber risk
Sep 22, 2026 GPT-6 Luna system card 4.5 Sandbox Bench, 1 of 22 targets (A.8.1.2.3) Cyber risk
Sep 3, 2026 GPT-6 Astra system card 45.5 Sandbox Bench, 10 of 22 targets (10.1.2.4) Cyber risk

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  • SRE-Bench In use Software reverse engineering without source: 262 binary instances from 19 private programs, each with six graded objectives. GPT-6 Astra 56.9%
  • CyScenarioBench In use Scenario-based long-horizon security challenges in sandboxes, organized in task, scenario and campaign tiers. Evaluation set kept private. Gemini 4 Argon 100%
  • ExploitBench - Internal Port In use Agents develop working exploits for recently disclosed vulnerabilities to limit contamination. Scored as arbitrary code execution success rate. GPT-6 Cyber 42%