# unCaptcha

defeating the latest version of ReCaptcha with 91% accuracy

Repository: https://github.com/ecthros/uncaptcha2
Canonical: https://ross.abutalabs.com/products/uncaptcha
Homepage: http://uncaptcha.cs.umd.edu
Language: Python
License Family: other
Last push: 2019-01-18T18:38:02+00:00
Link (homepage): http://uncaptcha.cs.umd.edu

## Health v2 (maintenance only)
Score: 32/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 0, release rhythm 35, longevity 100
- inputs: {"age_days": 2802, "days_push": 2784, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases, no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 4917, forks 449 (observed 2026-08-28T04:09:02.355794+00:00)

## What it is
unCaptcha2 is a Python-based security research tool that defeats Google's ReCaptcha v2 audio challenges by submitting the audio to free speech-to-text APIs and automating screen clicks, achieving roughly 90% accuracy. It was developed as academic research at the University of Maryland and released with Google's knowledge after responsible disclosure.

## Use cases
- demonstrate weaknesses in recaptcha audio challenges
- security research on captcha systems
- test captcha defenses on sites you control
- study speech-to-text abuse in automated attacks
- educational demonstration of low-resource captcha attacks

## When to choose
- you are a security researcher studying captcha vulnerabilities
- you need a reference implementation of audio captcha attacks for academic work
- you want to test your own site's captcha deployment

## When to avoid
- you need a maintained or supported tool - it is unmaintained since 2019 and ReCaptcha has since changed
- you want to bypass captchas on sites you do not own - that is unethical and often illegal
- you need a production-ready automation framework - coordinates must be manually configured per setup

## Facets
- artifact type: cli-tool
- maturity: abandoned
- function: speech-recognition, security, penetration-testing
- domain: security, speech-processing, artificial-intelligence
- platform: python
- tags: captcha-solving, recaptcha, security-research, screen-automation, academic-research, linux, desktop

## Member repositories
- ecthros/uncaptcha2 (main) score 32
- ecthros/uncaptcha (mirror) score 32

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:09:02.355794+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 2026-08-29T18:18:02.968886+00:00, confidence not recorded.
  - readme: https://github.com/ecthros/uncaptcha2 (fetched 2026-08-28T04:09:02.355794+00:00, sha 29442431e480)
  - homepage: http://uncaptcha.cs.umd.edu (fetched 2026-08-29T08:59:58.319245+00:00, sha 14ae6374ce93)
- Data as of 2026-08-30T08:39:29.467469+00:00.