{"cve":"CVE-2018-12399","nvd":{"published":"2019-02-28T18:29:01.023","modified":"2026-06-17T01:37:42.810","status":"Modified","description":"When a new protocol handler is registered, the API accepts a title argument which can be used to mislead users about which domain is registering the new protocol. This may result in the user approving a protocol handler that they otherwise would not have. This vulnerability affects Firefox < 63.","cvss_v4":null,"cvss_v3":{"version":"3.0","vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N","score":4.3},"cwes":["CWE-287"],"references":["http://www.securityfocus.com/bid/105721","http://www.securitytracker.com/id/1041944","https://bugzilla.mozilla.org/show_bug.cgi?id=1490276","https://usn.ubuntu.com/3801-1/","https://www.mozilla.org/security/advisories/mfsa2018-26/"],"products":["canonical:ubuntu_linux","mozilla:firefox"],"source":"nvd","synced_at":"2026-10-19T20:54:46.948512734+00:00"},"epss":{"cve":"CVE-2018-12399","score":0.01565,"percentile":0.75303,"date":"2026-10-31"},"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."]}