CVE-2017-5455: Mozilla Firefox

High severity, CVSS 7.5. EPSS: 3.5% chance of exploitation in the next 30 days.

The internal feed reader APIs that crossed the sandbox barrier allowed for a sandbox escape and escalation of privilege if combined with another vulnerability that resulted in remote code execution inside the sandboxed process. This vulnerability affects 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)
• Red Hat Enterprise Linux: version 7.0 only
• Red Hat Enterprise Linux Desktop: version 7.0 only
• Red Hat Enterprise Linux Server: 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 7.0 only

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