8.8

CVE-2021-22538: google llc exposure notifications verification server Improper Input Validation

CVSS: 8.8v3.1HighModified
AliasesGHSA-5v95-v8c8-3rh6GO-2022-0798
Published 31-03-2021Last modified 03-08-2024
Open JSON

Vulnerability summary

CVE-2021-22538 is a high (CVSS 8.8) Improper Input Validation vulnerability in google llc exposure notifications verification server. EPSS estimates a 0.72% chance of exploitation in the next 30 days, higher than 52.9% of scored vulnerabilities.

Overall risk
35/100
0100
Medium · default modelHow is this calculated?
CVSS score
8.8/10
010
High · v3.1 (NVD)
EPSS score
0.72%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 31-03-2021
    PublishedVulnerability first disclosed.
  2. 03-08-2024
    Last modifiedVulnerability information updated.

Description

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.

CVSS metrics

4 scores · 3 sources · 2 versions

EPSS trend

Probability

0.72%

Chance of exploitation in the next 30 days

Percentile

53%

Versus all other CVEs

30-day change

0.00 pp

From 0.72% on 18-09-2026

18-09-202618-10-2026
EPSS score
0.72%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Github.com/google1 product
  • exposure-notifications-verification-server< 0.23.1
Google1 product
Google llc1 product

3 vendors · 3 products

References

5 links