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gemini-3.1-pro-preview vs gpt-5.2-codex

Both models ran the same corpus under the same verifier — opencode and opencode respectively. The harness differs where the names differ, and that is part of what separates them.

Their confidence intervals overlap. On this corpus the difference of 17.1 points is not resolved — treat these two as tied.

opencode / gemini-3.1-pro-preview

54.9%

95% interval 42.9–66.7 · 122 attempts

54.9% (95% interval 42.9–66.7)
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opencode / gpt-5.2-codex

37.8%

95% interval 25.0–48.7 · 127 attempts

37.8% (95% interval 25.0–48.7)
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Where they differ

Weaknessgemini-3.1-pro-previewgpt-5.2-codexDifference
CWE-125Out-of-bounds Read62.5%41.3%+21.2
CWE-787Out-of-bounds Write50.0%41.2%+8.8
CWE-416Use After Free50.0%30.8%+19.2
CWE-908Use of Uninitialized Resource50.0%22.2%+27.8
CWE-415Double Free33.3%50.0%-16.7
CWE-1284Improper Validation of Specified Quantity in Input0.0%50.0%-50.0
CWE-843Access of Resource Using Incompatible Type ('Type Confusion')50.0%0.0%+50.0
CWE-476NULL Pointer Dereference0.0%0.0%0.0
CWE-475100.0%0.0%+100.0
CWE-5620.0%100.0%-100.0

Per-class samples are small; a difference here is a hint about where to look, not a result. The corpus-level intervals above are the honest comparison.

Corpus cve-bench-136 · run February 2026 · How we test

See the benchmark →