CVE-2019-17020: Canonical Ubuntu Linux

Medium severity, CVSS 6.5. EPSS: 1.1% chance of exploitation in the next 30 days.

If an XML file is served with a Content Security Policy and the XML file includes an XSL stylesheet, the Content Security Policy will not be applied to the contents of the XSL stylesheet. If the XSL sheet e.g. includes JavaScript, it would bypass any of the restrictions of the Content Security Policy applied to the XML document. This vulnerability affects Firefox < 72.

Affected products

• Canonical Ubuntu Linux: version 16.04 only; version 18.04 only; version 19.04 only; version 19.10 only
• Mozilla Firefox: before 72.0 (fixed in 72.0)

Published 2020-01-08. Last modified 2026-06-17.