CVE-2017-5456: Mozilla Firefox

Critical severity, CVSS 9.8. EPSS: 2.8% chance of exploitation in the next 30 days.

A mechanism to bypass file system access protections in the sandbox using the file system request constructor through an IPC message. This allows for read and write access to the local file system. 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.