Arc before 2024-08-26 allows remote code execution in JavaScript boosts. Boosts that run JavaScript cannot be shared by default; however (because of misconfigured Firebase ACLs), it is possible to create or update a boost using another user's ID. This installs the boost in the victim's browser and runs arbitrary Javascript on that browser in a privileged context. NOTE: this is a no-action cloud vulnerability with zero affected users.

Address bar spoofing risk in ArcSearch on Android

ArcSearch for Android versions prior to 1.12.6 could display a different domain in the address bar than the content being shown, enabling address bar spoofing after user interaction via crafted web content.

Address bar spoofing risk in Arc Search on iOS

ArcSearch for iOS versions prior to 1.45.2 could display a different domain in the address bar than the content being shown after an iframe-triggered URI-scheme navigation, increasing spoofing risk.