Improper input validation in Google Exposure Notifications Verification Server

CVE-2021-22538

A privilege escalation vulnerability impacting the Google Exposure Notification Verification Server (versions prior to 0.23.1), allows an attacker who (1) has UserWrite permissions and (2) is using a carefully crafted request or malicious proxy, to create another user with higher privileges than their own. This occurs due to insufficient checks on the allowed set of permissions. The new user creation event would be captured in the Event Log.

Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)

EPSS: 0.007 (50.1th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2021-22538?
CVE-2021-22538 is a medium-severity vulnerability in Google Exposure Notifications Verification Server, classified under Improper Input Validation. CVSS score: 6.3/10. Published 2021-03-31.
How severe is CVE-2021-22538?
Medium severity. CVSS v3 base score is 6.3 out of 10.