Until explicitly accessed by script, window.globalThis is not enumerable and,...

Vulnerability Description

Until explicitly accessed by script, window.globalThis is not enumerable and, as a result, is not visible to code such as Object.getOwnPropertyNames(window). Sites that deploy a sandboxing that depends on enumerating and freezing access to the window object may miss this, allowing their sandboxes to be bypassed. This vulnerability affects Firefox < 68.

References

• https://www.mozilla.org/security/advisories/mfsa2019-21/
• https://bugzilla.mozilla.org/show_bug.cgi?id=1552632
• https://security.gentoo.org/glsa/201908-12
• http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00010.html
• http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00009.html
• http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00011.html
• http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00017.html