CVE-2017-7838: Mozilla Firefox

Medium severity, CVSS 5.3. EPSS: 1.5% chance of exploitation in the next 30 days.

Punycode format text will be displayed for entire qualified international domain names in some instances when a sub-domain triggers the punycode display instead of the primary domain being displayed in native script and the sub-domain only displaying as punycode. This could be used for limited spoofing attacks due to user confusion. This vulnerability affects Firefox < 57.

Affected products

• Mozilla Firefox: up to and including 56.0.2

Published 2018-06-11. Last modified 2026-06-17.