# diffblue/cbmc

C Bounded Model Checker

Repository: https://github.com/diffblue/cbmc
Canonical: https://ross.abutalabs.com/products/cbmc
Homepage: https://diffblue.github.io/cbmc
Language: C++
License: NOASSERTION
License Family: other
Last push: 2026-08-21T03:32:14+00:00

## Health v2 (maintenance only)
Score: 94/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 98, release rhythm 86, longevity 100
- inputs: {"age_days": 3851, "days_push": 12, "days_rel": 12, "gap_med": 52.0, "n_releases_24m": 13}
- flags: no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1109, forks 299 (observed 2026-08-28T04:03:37.066403+00:00)

## What it is
CBMC (C Bounded Model Checker) is a formal verification tool for C and C++ programs that explores all possible execution paths on bounded inputs to check assertions, memory safety, and undefined behavior. It works by unwinding loops and passing the resulting formula to a decision procedure (SMT solver).

## Use cases
- verify C programs for buffer overflows and array bounds violations
- check pointer safety and memory errors in C/C++ code
- detect undefined behavior like signed integer overflow
- prove user-specified assertions hold on all bounded inputs
- verify C code consistency against Verilog hardware designs
- formally verify embedded or safety-critical C code
- find bugs via exhaustive path exploration instead of sampling test inputs

## When to choose
- you need formal guarantees about C/C++ code correctness for bounded inputs
- you want exhaustive checking of memory safety and undefined behavior rather than fuzzing
- you are verifying safety-critical or embedded C code
- you need to check equivalence between C and hardware description languages

## When to avoid
- your codebase has deep or unbounded loops/recursion that cannot be practically unwound
- you only need lightweight static analysis or linting
- you need runtime testing or fuzzing rather than formal verification
- you work primarily in languages other than C/C++

## Facets
- artifact type: cli-tool
- maturity: active
- function: testing, security, developer-tools
- domain: developer-tools, security, testing
- platform: windows, cpp, cli
- tags: bounded-model-checking, formal-verification, model-checking, c-verification, cpp-verification, memory-safety, smt-solver, assertion-checking, undefined-behavior, algorithms, linux, macos

## Member repositories
- diffblue/cbmc (main) score 94

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:03:37.066403+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T06:43:34.672476+00:00, confidence not recorded.
  - readme: https://github.com/diffblue/cbmc (fetched 2026-08-28T04:03:37.066403+00:00, sha bd0dcbeba8e6)
  - homepage: https://diffblue.github.io/cbmc (fetched 2026-08-29T12:47:04.355625+00:00, sha f9e6759140b8)
- Data as of 2026-08-30T08:39:29.467469+00:00.