CVE-2021-22538

CVE-2021-22538 is a high-severity privilege escalation vulnerability affecting Google Exposure Notification Verification Server versions prior to 0.23.1. An authenticated attacker with UserWrite permissions can craft a malicious request to create a new user with elevated privileges due to insufficient permission checks. This vulnerability has a CVSS score of 8.8, indicating a high impact on confidentiality, integrity, and availability. There is no public exploit code available, nor is there evidence of active exploitation or significant community discussion.