{"cve":"CVE-2019-9801","nvd":{"published":"2019-04-26T17:29:02.977","modified":"2026-06-17T02:44:25.757","status":"Modified","description":"Firefox will accept any registered Program ID as an external protocol handler and offer to launch this local application when given a matching URL on Windows operating systems. This should only happen if the program has specifically registered itself as a \"URL Handler\" in the Windows registry. *Note: This issue only affects Windows operating systems. Other operating systems are unaffected.*. This vulnerability affects Thunderbird < 60.6, Firefox ESR < 60.6, and Firefox < 66.","cvss_v4":null,"cvss_v3":{"version":"3.0","vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","score":5.3},"cwes":["CWE-20"],"references":["https://bugzilla.mozilla.org/show_bug.cgi?id=1527717","https://www.mozilla.org/security/advisories/mfsa2019-07/","https://www.mozilla.org/security/advisories/mfsa2019-08/","https://www.mozilla.org/security/advisories/mfsa2019-11/","https://bugzilla.mozilla.org/show_bug.cgi?id=1527717"],"products":["mozilla:firefox","mozilla:firefox_esr","mozilla:thunderbird"],"source":"nvd","synced_at":"2026-10-19T20:56:19.218283075+00:00"},"epss":{"cve":"CVE-2019-9801","score":0.0131,"percentile":0.70654,"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."]}