Shared Tab Groups is a browser feature that lets a set of tabs be synchronized and shared across users or devices. Instead of living only in one local window, the group can be copied, updated, or reopened from another browser session, which makes it useful for collaboration and continuity.
In security terms, shared state increases complexity. The browser must track ownership, permissions, updates, and object lifetimes across multiple sessions, which creates opportunities for logic bugs and memory-safety flaws. If that code is weak, an attacker may be able to trigger crashes, corrupt state, or in some cases build a path toward exploitation. Defenders care because features that sync data are often trusted by default, so bugs can spread quickly across normal workflows. Good protection means keeping the browser patched, limiting exposure to untrusted content, and testing synchronization features as carefully as rendering or networking code.