Zen is a firefox-based browser. Prior to 1.21.5b, Zen's glance and split-view context-menu actions, Open link in glance and Split link in new tab, load a page-controlled link URL with the System principal instead of the originating page's principal, allowing a malicious web page to place a link to a file URL that can load with System privileges when opened through either context-menu item and bypass the content-to-file security check that blocks an ordinary click. This issue is fixed in version 1.21.5b.