{"cve":"CVE-2021-4221","nvd":{"published":"2022-12-22T20:15:12.337","modified":"2026-06-17T04:19:14.537","status":"Modified","description":"If a domain name contained a RTL character, it would cause the domain to be rendered to the right of the path. This could lead to user confusion and spoofing attacks. <br>*This bug only affects Firefox for Android. Other operating systems are unaffected.*<br>*Note*: Due to a clerical error this advisory was not included in the original announcement, and was added in Feburary 2022. This vulnerability affects Firefox < 92.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N","score":4.3},"cwes":["CWE-1007"],"references":["https://bugzilla.mozilla.org/show_bug.cgi?id=1704422","https://www.mozilla.org/security/advisories/mfsa2021-38/","https://bugzilla.mozilla.org/show_bug.cgi?id=1704422","https://www.mozilla.org/security/advisories/mfsa2021-38/"],"products":["mozilla:firefox"],"source":"nvd","synced_at":"2026-10-19T21:37:31.370122805+00:00"},"epss":{"cve":"CVE-2021-4221","score":0.0043,"percentile":0.37267,"date":"2026-11-01"},"kev":null,"osv":[],"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."]}