CVE-2018-5138
A spoofing vulnerability can occur when a malicious site with an extremely long domain name is opened in an Android Custom Tab (a browser panel inside another app) and the default browser is Firefox for Android.
Does this matter?
Lower severity and a low EPSS score (1.09%). Track it; it rarely justifies an emergency change on its own.
Description
A spoofing vulnerability can occur when a malicious site with an extremely long domain name is opened in an Android Custom Tab (a browser panel inside another app) and the default browser is Firefox for Android. This could allow an attacker to spoof which page is actually loaded and in use. Note: this issue only affects Firefox for Android. Other versions and operating systems are unaffected. This vulnerability affects Firefox < 59.
- CVSS 3.0
- 5.3 MEDIUMCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
- EPSS
- 1.09% probability · 65th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-20
- Affected
- mozilla/firefox
- Source
- security@mozilla.org
EPSS 1.1% since 27 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- http://www.securityfocus.com/bid/103386Third Party Advisory, VDB Entry
- http://www.securitytracker.com/id/1040514Third Party Advisory, VDB Entry
- https://bugzilla.mozilla.org/show_bug.cgi?id=1432624Issue Tracking, Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2018-06/Vendor Advisory
- http://www.securityfocus.com/bid/103386Third Party Advisory, VDB Entry
- http://www.securitytracker.com/id/1040514Third Party Advisory, VDB Entry
- https://bugzilla.mozilla.org/show_bug.cgi?id=1432624Issue Tracking, Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2018-06/Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.