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.
cuando un iframe tiene un atributo "sandbox" y su contenido se especifica mediante "srcdoc", dicho contenido no hereda el CSP (Content Security Policy) de la página que lo contiene, tal y como debería, a no ser que el atributo sandbox incluya "allow-same-origin". La vulnerabilidad afecta a Firefox en versiones anteriores a la 55.
USN-3391-1 fixed vulnerabilities in Firefox. The update introduced a performance regression with WebExtensions. This update fixes the problem. Multiple security issues were discovered in Firefox. If a user were tricked in to opening a specially crafted website, an attacker could potentially exploit these to conduct cross-site scripting attacks, bypass sandbox restrictions, obtain sensitive information, spoof the origin of modal alerts, bypass same origin restrictions, read uninitialized memory, cause a denial of service via program crash or hang, or execute arbitrary code. Various other issues were also addressed.
