# googleprojectzero/winafl

A fork of AFL for fuzzing Windows binaries

Repository: https://github.com/googleprojectzero/winafl
Canonical: https://ross.abutalabs.com/products/winafl
Language: C
License: Apache-2.0
License Family: permissive
Topics: fuzzing, security, afl
Last push: 2026-03-13T12:56:22+00:00

## Health v2 (maintenance only)
Score: 65/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 72, release rhythm 35, longevity 100
- inputs: {"age_days": 3709, "days_push": 173, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 2604, forks 560 (observed 2026-08-28T04:07:03.504446+00:00)

## What it is
WinAFL is a Windows fork of American Fuzzy Lop (AFL) for coverage-guided fuzzing of Windows binaries, including closed-source black-box targets. It uses dynamic instrumentation via DynamoRIO or TinyInst, Intel PT hardware tracing, or Syzygy static instrumentation, with persistent fuzzing to reduce process restart overhead.

## Use cases
- fuzz windows binaries for vulnerabilities
- fuzz closed-source black-box windows applications
- find memory corruption bugs in windows software
- coverage-guided fuzzing without recompiling the target
- fuzz a specific function in a windows dll
- discover cves in windows desktop software

## When to choose
- you need to fuzz windows executables or dlls
- you cannot recompile the target with source instrumentation
- you want proven coverage-guided fuzzing on windows
- you want to fuzz a single target function persistently

## When to avoid
- you are fuzzing on linux or macos where original AFL or AFL++ works
- you need to fuzz source-available targets with full compile-time instrumentation
- you need structured protocol or kernel fuzzing with specialized tooling

## Facets
- artifact type: cli-tool
- maturity: active
- function: fuzzing, security, testing
- domain: security, penetration-testing, developer-tools, windows
- platform: windows, cli
- tags: afl, coverage-guided-fuzzing, dynamorio, tinyinst, intel-pt, black-box-fuzzing, persistent-fuzzing, vulnerability-discovery

## Member repositories
- googleprojectzero/winafl (main) score 65

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:07:03.504446+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 2026-08-30T02:21:06.166202+00:00, confidence not recorded.
  - readme: https://github.com/googleprojectzero/winafl (fetched 2026-08-28T04:07:03.504446+00:00, sha fd7879fa9762)
- Data as of 2026-08-30T08:39:29.467469+00:00.