Google Gemini 2.5 Pro vs Google Gemini 2.0 Flash Thinking

Detailed comparison for LLMs

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On Guardion's LLM vulnerability Benchmark, Google Gemini 2.5 Pro is the more secure of the two: Gemini 2.5 Pro scores 16.1% and Gemini 2.0 Flash Thinking scores 21.5% on attack success rate (ASR) (lower is better). One or both scores are estimated from public safety evaluations pending a Guardion benchmark run.

Head-to-Head Overview

Gemini 2.5 Pro is the overall winner in this comparison!

Attack Success Rate (lower is safer)

ASR for Google Gemini 2.5 Pro vs Google Gemini 2.0 Flash Thinking. Green marks the safer model on each metric. Only the overall score is available for estimated models.

Overall (ASR)

Gemini 2.5 Pro
16.1%
Gemini 2.0 Flash Thinking
21.5%

TAP Attack Method (ASR)

Gemini 2.5 Pro
27.5%
Gemini 2.0 Flash Thinking
100.0%

Crescendo Attack Method (ASR)

Gemini 2.5 Pro
19.1%
Gemini 2.0 Flash Thinking
100.0%

Zero-Shot (ASR)

Gemini 2.5 Pro
1.6%
Gemini 2.0 Flash Thinking
100.0%

Key Highlights

  • Google Gemini 2.5 Pro has a lower Overall (ASR).
  • Google Gemini 2.5 Pro has a lower TAP Attack Method (ASR).
  • Google Gemini 2.5 Pro has a lower Crescendo Attack Method (ASR).
  • Google Gemini 2.5 Pro has a lower Zero-Shot (ASR).

Security Profile

Outward is better on every axis.

OverallTAPCrescendoZero-Shot
Gemini 2.5 Pro
Gemini 2.0 Flash Thinking
Full security profile
Google Gemini 2.5 Pro
Full security profile
Google Gemini 2.0 Flash Thinking

Frequently asked questions

Is Google Gemini 2.5 Pro or Google Gemini 2.0 Flash Thinking more secure?

On Guardion's LLM vulnerability Benchmark, Google Gemini 2.5 Pro is the more secure of the two: Gemini 2.5 Pro scores 16.1% and Gemini 2.0 Flash Thinking scores 21.5% on attack success rate (ASR) (lower is better). One or both scores are estimated from public safety evaluations pending a Guardion benchmark run.

What is the attack success rate (ASR) of Gemini 2.5 Pro vs Gemini 2.0 Flash Thinking?

Gemini 2.5 Pro has a 16.1% ASR and Gemini 2.0 Flash Thinking has a 21.5% ASR — the share of adversarial prompts that succeed across zero-shot, TAP, and Crescendo attacks. Lower is safer.

How were Gemini 2.5 Pro and Gemini 2.0 Flash Thinking tested?

Both were red-teamed with the HarmBench framework across zero-shot, TAP (Tree of Attacks with Pruning), and Crescendo multi-turn attacks, scored by Attack Success Rate.

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