---
id: CVE-2021-22538
aliases:
  - GHSA-5v95-v8c8-3rh6
  - GO-2022-0798
title: Privilege escalation in rbac
summary: Privilege escalation in rbac
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
vendor: google
product: github.com/google/exposure-notifications-verification-server
ecosystem: go
affected:
  - github.com/google/exposure-notifications-verification-server < 0.23.1
patched:
  - github.com/google/exposure-notifications-verification-server 0.23.1
published: '2021-05-21'
updated: '2026-07-08'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-5v95-v8c8-3rh6'
references:
  - url: >-
      https://github.com/google/exposure-notifications-verification-server/security/advisories/GHSA-5v95-v8c8-3rh6
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2021-22538'
  - url: >-
      https://github.com/google/exposure-notifications-verification-server/commit/eb8cf40b12dbe79304f1133c06fb73419383cd95
  - url: >-
      https://github.com/google/exposure-notifications-verification-server/releases/tag/v0.23.1
  - url: >-
      https://github.com/google/exposure-notifications-verification-server/releases/tag/v0.24.0
tags:
  - osv
  - go
epss: 0.00718
epssPercentile: 0.51844
ingestedAt: '2026-07-09T18:56:35.950Z'
---

## Overview

### Impact
Using a carefully crafted request or malicious proxy, a user with `UserWrite` permissions could create another user with higher privileges than their own due to insufficient checks on the allowed set of permissions. The event would be captured in the Event Log.

### Patches
The issue has been fixed in 0.24.0 and 0.23.1.

### Workarounds
For users who are unable to upgrade, we recommend auditing users who have `UserWrite` permissions and regularly reviewing the Event Log for malicious activity.

### Kudos
Thank you to Michael Mazzolini (Ethical Hacker at WHO) for finding and disclosing this vulnerability.

## Affected packages

- `github.com/google/exposure-notifications-verification-server < 0.23.1`

## Remediation

Upgrade to a patched release:

- `github.com/google/exposure-notifications-verification-server 0.23.1`