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CVE-2019-9801
Firefox will accept any registered Program ID as an external protocol handler and offer to launch this local application when given a…
Medium5.3EPSS 1.3%
- Published
- Updated
- Reserved
- Assigned by
- mozilla
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.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Modified | 3.0 | Medium5.3 | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
- EPSS (exploitation in 30 days)
- 1.3% · top 29% of all CVEs (5 Nov 2026)
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The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.3.
Weakness
- Windows programs that are not 'URL Handlers' are exposed to web content
- CWE-20 (opens in a new tab)All about CWE-20 and its CVEs
Affected products
- affected unspecified – < 60.6
- affected unspecified – < 60.6
- affected unspecified – < 66
References (4)
- https://www.mozilla.org/security/advisories/mfsa2019-07/ (opens in a new tab)x_refsource_MISCx_transferred
- https://www.mozilla.org/security/advisories/mfsa2019-08/ (opens in a new tab)x_refsource_MISCx_transferred
- https://www.mozilla.org/security/advisories/mfsa2019-11/ (opens in a new tab)x_refsource_MISCx_transferred
- https://bugzilla.mozilla.org/show_bug.cgi?id=1527717 (opens in a new tab)x_refsource_MISCx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2019-9801)Record last updated .