CVE-2021-21208: 
Google Chrome vulnerability analysis and mitigation

CVE-2021-21208 is a security vulnerability affecting the QR scanner functionality in Google Chrome on iOS versions prior to 90.0.4430.72. The vulnerability was discovered by Ahmed Elsobky and reported on January 7, 2020. The issue stems from insufficient data validation in the QR scanner component, which could allow an attacker to perform domain spoofing through a crafted QR code (NVD, Chrome Blog).

The vulnerability is classified as a medium severity issue related to insufficient data validation in the QR scanner component. The bug was assigned a bounty of $3,000, indicating its moderate impact level. The vulnerability was tracked internally as bug #1039539 and was fixed in Chrome version 90.0.4430.72 (Chrome Blog).

The vulnerability could allow an attacker to perform domain spoofing by displaying a specially crafted QR code to users. This could potentially lead to users being directed to malicious websites while believing they are visiting legitimate domains (NVD).

The vulnerability was addressed in Google Chrome version 90.0.4430.72 and later versions. Users and administrators are advised to upgrade to this version or newer to mitigate the risk. Multiple Linux distributions including Debian, Fedora, and Gentoo have also released security updates to address this vulnerability (Debian Security, Gentoo Security).