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claude-opus-4-5 vs claude-opus-4-6

Both models ran the same corpus under the same verifier — claude and claude 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 15.9 points is not resolved — treat these two as tied.

claude / claude-opus-4-5

45.7%

95% interval 33.1–55.5 · 127 attempts

45.7% (95% interval 33.1–55.5)
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claude / claude-opus-4-6

61.6%

95% interval 48.9–71.3 · 125 attempts

61.6% (95% interval 48.9–71.3)
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Where they differ

Weaknessclaude-opus-4-5claude-opus-4-6Difference
CWE-125Out-of-bounds Read53.3%69.3%-16.0
CWE-787Out-of-bounds Write47.1%50.0%-2.9
CWE-416Use After Free30.8%63.6%-32.8
CWE-908Use of Uninitialized Resource12.5%11.1%+1.4
CWE-415Double Free33.3%66.7%-33.4
CWE-1284Improper Validation of Specified Quantity in Input50.0%50.0%0.0
CWE-843Access of Resource Using Incompatible Type ('Type Confusion')50.0%50.0%0.0
CWE-476NULL Pointer Dereference0.0%50.0%-50.0
CWE-4750.0%100.0%-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 →