CVE-2017-7788: Mozilla: Sandboxed about:srcdoc frames do not inherit CSP directives (MFSA 2017-18)

Severity: Critical

CVSS Score: 9.8

When an "iframe" has a "sandbox" attribute and its content is specified using "srcdoc", that content does not inherit the containing page's Content Security Policy (CSP) as it should unless the sandbox attribute included "allow-same-origin". This vulnerability affects Firefox < 55.