CVE-2018-5126: Canonical Ubuntu Linux

Critical severity, CVSS 9.8. EPSS: 1.7% chance of exploitation in the next 30 days.

Memory safety bugs were reported in Firefox 58. Some of these bugs showed evidence of memory corruption and we presume that with enough effort that some of these could be exploited to run arbitrary code. This vulnerability affects Firefox < 59.

Affected products

• Canonical Ubuntu Linux: version 14.04 only; version 16.04 only; version 17.10 only
• Mozilla Firefox: before 59.0 (fixed in 59.0)

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