{"cve":"CVE-2021-3424","nvd":{"published":"2021-06-01T19:15:07.557","modified":"2026-06-17T04:05:03.853","status":"Modified","description":"A flaw was found in keycloak as shipped in Red Hat Single Sign-On 7.4 where IDN homograph attacks are possible. A malicious user can register himself with a name already registered and trick admin to grant him extra privileges.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","score":5.3},"cwes":["CWE-287"],"references":["https://bugzilla.redhat.com/show_bug.cgi?id=1933320","https://bugzilla.redhat.com/show_bug.cgi?id=1933320"],"products":["redhat:single_sign-on"],"source":"nvd","synced_at":"2026-10-19T21:18:09.669877188+00:00"},"epss":{"cve":"CVE-2021-3424","score":0.00774,"percentile":0.55748,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-pf38-cw3p-22q9","url":"https://osv.dev/vulnerability/GHSA-pf38-cw3p-22q9","summary":"Keycloak is vulnerable to IDN homograph attack","modified":"2023-11-08T04:06:07.448525Z","packages":[{"ecosystem":"Maven","name":"org.keycloak:keycloak-services","purl":"pkg:maven/org.keycloak/keycloak-services","ranges":["<18.0.0"],"fixed":["18.0.0"]}]}],"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."]}