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returned=1 errno=0 peeraddr=140.82.121.5:443 state=error: unexpected eof while reading","robots_txt_status":"success","robots_txt_updated_at":"2025-07-24T06:49:26.215Z","robots_txt_url":"https://github.com/robots.txt","online":false,"can_crawl_api":true,"host_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub","repositories_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories","repository_names_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repository_names","owners_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners"}},"keywords":["bugbounty","bypass","cors","pentesting","vulnerability-scanners"],"created_at":"2024-08-04T17:01:24.596Z","updated_at":"2026-01-12T10:25:50.089Z","avatar_url":"https://github.com/wfinn.png","language":"Go","funding_links":[],"categories":["Go"],"sub_categories":[],"readme":"# ucors?\n\nTool that finds CORS misconfigurations.\n\n```sh\ngo install github.com/wfinn/ucors@latest\n\n$ echo https://target.tld/endpoint | ucors\n$ cat urls.txt | ucors -c session=xyz123\nUrl: https://target.tld/endpoint Origin: null ACAC: true\n...\n```\n\nMany bypasses only work in Safari.\n\n## Payloads\n- usual reflection e.g. http(s)://evil.com\n- https://target.tld.evil.com\n- https://target.tldevil.com\n- null (sandboxed iframes can have origin null)\n- unescaped dots in regexes e.g. https://wwwxtarget.tld\n- different TLDs e.g. https://target.wtf\n- unexpected chars in subdomains https://target.tld\u0026.evil.com\n- Bonus check: xss on subdomains https://any.target.tld\n\n## Usage\n\nCreate a list of urls to check, (grab a valid session cookie) and start ucors to find some bypasses.  \nIdeally you prepare a list of all endpoints returning interesting data.\n\nBelow is an example output, you see the url, the payload that worked and if cookies are allowed\n```sh\n$ cat urls.txt | ucors -c session=xyz123\nUrl: https://target.tld/profile/private-data.json Origin: https://subdomain.target.tld\u0026evil.com ACAC: true\nUrl: https://sub.target.tld/getSensitiveInfo Origin: null ACAC: true\n...\n```\n\n### Flags\n- -p to only print the generated bypasses and not make any requests\n- -d evil.com to set the attacker domain\n- -s to skip the url after finding a bypass\n- -c abc=XYZ to set cookies\n- -a \"Bearer: abcXYZ\" to set the Authorization header\n\n## Resources\n- https://portswigger.net/web-security/cors\n- https://www.corben.io/advanced-cors-techniques/\n\n---\n\nThis is based on [@tomnomnom's cors-blimey](https://github.com/tomnomnom/hacks/tree/master/cors-blimey).\n","project_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fwfinn%2Fucors","html_url":"https://awesome.ecosyste.ms/projects/github.com%2Fwfinn%2Fucors","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fwfinn%2Fucors/lists"}