CVE-2018-12399

4.3 mediumEPSS 1.6%

Medium (4.3). EPSS 1.6% chance of exploitation in the next 30 days.

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.

Severity

CVSS 3.0

4.3 medium

CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

EPSS: 1.6% chance of exploitation in the next 30 days; higher than 75% of CVEs (scores of 2026-10-31)
CWE: CWE-287
Published: 2019-02-28
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

canonical:ubuntu_linux
mozilla:firefox

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/

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