{"cve":"CVE-2020-15234","nvd":{"published":"2020-10-02T21:15:12.513","modified":"2026-06-17T02:56:19.587","status":"Modified","description":"ORY Fosite is a security first OAuth2 & OpenID Connect framework for Go. In Fosite before version 0.34.1, the OAuth 2.0 Client's registered redirect URLs and the redirect URL provided at the OAuth2 Authorization Endpoint where compared using strings.ToLower while they should have been compared with a simple string match. This allows an attacker to register a client with allowed redirect URL https://example.com/callback. Then perform an OAuth2 flow and requesting redirect URL https://example.com/CALLBACK. Instead of an error (invalid redirect URL), the browser is redirected to https://example.com/CALLBACK with a potentially successful OAuth2 response, depending on the state of the overall OAuth2 flow (the user might still deny the request for example). This vulnerability has been patched in ORY Fosite v0.34.1.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N","score":4.8},"cwes":["CWE-178","CWE-20","CWE-601"],"references":["https://github.com/ory/fosite/commit/cdee51ebe721bfc8acca0fd0b86b030ca70867bf","https://github.com/ory/fosite/security/advisories/GHSA-grfp-q2mm-hfp6","https://github.com/ory/fosite/commit/cdee51ebe721bfc8acca0fd0b86b030ca70867bf","https://github.com/ory/fosite/security/advisories/GHSA-grfp-q2mm-hfp6"],"products":["ory:fosite"],"source":"nvd","synced_at":"2026-10-19T21:09:53.489947993+00:00"},"epss":{"cve":"CVE-2020-15234","score":0.00841,"percentile":0.5791,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-grfp-q2mm-hfp6","url":"https://osv.dev/vulnerability/GHSA-grfp-q2mm-hfp6","summary":"Redirect URL matching ignores character casing","modified":"2026-09-10T03:49:26.784913554Z","packages":[{"ecosystem":"Go","name":"github.com/ory/fosite","purl":"pkg:golang/github.com/ory/fosite","ranges":["<0.34.1"],"fixed":["0.34.1"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}