CVE-2018-5136: Canonical Ubuntu Linux

High severity, CVSS 7.5. EPSS: 1.6% chance of exploitation in the next 30 days.

A shared worker created from a "data:" URL in one tab can be shared by another tab with a different origin, bypassing the same-origin policy. 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.