CVE-2017-5391: Mozilla Firefox

Critical severity, CVSS 9.8. EPSS: 1.8% chance of exploitation in the next 30 days.

Special "about:" pages used by web content, such as RSS feeds, can load privileged "about:" pages in an iframe. If a content-injection bug were found in one of those pages this could allow for potential privilege escalation. This vulnerability affects Firefox < 51.

Affected products

• Mozilla Firefox: before 51.0 (fixed in 51.0)

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