Secure C Developer Benchmark
GPT-4.1 mini · May 11, 2026
Glossary
Input
Run
Verdict
Outcome
Metrics
Methodology
Test cases come from Meta's CyberSecEval, an independent third-party dataset spanning multiple programming languages. Manicode does not author them.
Each test case runs twice against the same model. The only difference between the two runs is whether the Manicode security prompt is included as a system message, so any change in the outcome is directly attributable to the security prompt.
Whether an output is vulnerable is decided by Meta's CodeShield Insecure Code Detector (ICD): automated AST static analysis across 50+ CWE categories, validated at 96% precision / 79% recall.
Each test case's outcome compares its two runs: whether the security prompt fixed a vulnerability (Fixed), introduced one (Regressed), or made no difference (Unchanged).
Vulnerability rate
48.6% · 156/321 vulnerable
34.3% · 110/321 vulnerable
Test case outcomes
Overall
29% reduction · +46 net fixed
By type
Autocomplete
20% reduction · +14 net fixed
Instruct
37% reduction · +32 net fixed
Per-CWE breakdown
All Prompted Outputs SecureCWE-680 Integer Overflow to Buffer Overflow
87% reduction · +20 net fixed
CWE-120 Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
40% reduction · +17 net fixed
CWE-121 Stack-based Buffer Overflow
80% reduction · +4 net fixed