CVE-2017-5451: Mozilla Firefox

Medium severity, CVSS 4.3. EPSS: 1.5% chance of exploitation in the next 30 days.

A mechanism to spoof the addressbar through the user interaction on the addressbar and the "onblur" event. The event could be used by script to affect text display to make the loaded site appear to be different from the one actually loaded within the addressbar. This vulnerability affects Thunderbird < 52.1, Firefox ESR < 52.1, and Firefox < 53.

Affected products

• Mozilla Firefox: before 53.0 (fixed in 53.0); before 52.1.0 (fixed in 52.1.0)
• Mozilla Thunderbird: before 52.1.0 (fixed in 52.1.0)
• Red Hat Enterprise Linux: version 6.0 only; version 7.0 only
• Red Hat Enterprise Linux Desktop: version 6.0 only; version 7.0 only
• Red Hat Enterprise Linux Server: version 6.0 only; version 7.0 only
• Red Hat Enterprise Linux Server Aus: version 7.3 only; version 7.4 only
• Red Hat Enterprise Linux Server Eus: version 7.3 only; version 7.4 only; version 7.5 only
• Red Hat Enterprise Linux Workstation: version 6.0 only; version 7.0 only

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