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gpt-5.2 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 13.8 points is not resolved — treat these two as tied.

opencode / gpt-5.2

51.6%

95% interval 39.5–63.1 · 122 attempts

51.6% (95% interval 39.5–63.1)
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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

Weaknessgpt-5.2gpt-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 Free33.3%30.8%+2.5
CWE-908Use of Uninitialized Resource22.2%22.2%0.0
CWE-415Double Free66.7%50.0%+16.7
CWE-1284Improper Validation of Specified Quantity in Input0.0%50.0%-50.0
CWE-476NULL Pointer Dereference0.0%0.0%0.0
CWE-843Access of Resource Using Incompatible Type ('Type Confusion')0.0%0.0%0.0
CWE-4750.0%0.0%0.0
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 →