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.
https://bugzilla.mozilla.org/show_bug.cgi?id=1527717
https://www.mozilla.org/security/advisories/mfsa2019-07/
Source: MITRE
Published: 2019-04-26
Updated: 2019-04-29
Type: CWE-20
Base Score: 5
Vector: AV:N/AC:L/Au:N/C:N/I:P/A:N
Impact Score: 2.9
Exploitability Score: 10
Severity: MEDIUM
Base Score: 5.3
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Impact Score: 1.4
Exploitability Score: 3.9
Severity: MEDIUM