CVE-2018-12387: Canonical Ubuntu Linux

Critical severity, CVSS 9.1. EPSS: 9.6% chance of exploitation in the next 30 days.

A vulnerability where the JavaScript JIT compiler inlines Array.prototype.push with multiple arguments that results in the stack pointer being off by 8 bytes after a bailout. This leaks a memory address to the calling function which can be used as part of an exploit inside the sandboxed content process. This vulnerability affects Firefox ESR < 60.2.2 and Firefox < 62.0.3.

Affected products

• Canonical Ubuntu Linux: version 14.04 only; version 16.04 only; version 18.04 only
• Debian Debian Linux: version 9.0 only
• Mozilla Firefox: before 60.2.2 (fixed in 60.2.2); before 62.0.3 (fixed in 62.0.3)
• 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 7.6 only
• Red Hat Enterprise Linux Server Eus: version 7.5 only; version 7.6 only
• Red Hat Enterprise Linux Server Tus: version 7.6 only
• Red Hat Enterprise Linux Workstation: version 6.0 only; version 7.0 only

Published 2018-10-18. Last modified 2026-06-17.