CVE-2021-30533

A Chromium PopupBlocker vulnerability allowed attackers to bypass navigation restrictions via crafted iframes, impacting multiple browsers including Chrome and Edge, and actively exploited in the wild.

An insufficient policy enforcement flaw in the Chromium PopupBlocker enabled attackers to bypass navigation restrictions, potentially leading to malicious website access and data compromise. DIB organizations using Chromium-based browsers must promptly patch and review navigation policies to mitigate this risk and maintain NIST 800-171 compliance. This highlights the importance of timely patching and third-party component risk management.

Shame score — The vulnerability's active exploitation and broad impact across multiple browsers demonstrates a significant policy enforcement failure with avoidable consequences.