---
id: CVE-2021-30120
title: Kaseya VSA before 9.5.7 allows attackers to bypass the 2FA requirement
summary: >-
  Kaseya VSA before 9.5.7 allows attackers to bypass the 2FA requirement. The
  need to use 2FA for authentication in enforce client-side instead of
  server-side and can be bypassed using a local proxy. Thus rendering 2FA
  useless. Detailed de…
severity: critical
cvss: 9.9
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H'
cwe:
  - CWE-669
vendor: kaseya
product: vsa
affected:
  - vsa <= 9.5.6
published: '2021-07-09'
updated: '2026-08-14'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2021-30120'
references:
  - url: 'https://csirt.divd.nl/2021/07/07/Kaseya-Limited-Disclosure/'
    label: cve@mitre.org
  - url: 'https://csrit.divd.nl/CVE-2021-30120'
    label: cve@mitre.org
  - url: 'https://csrit.divd.nl/DIVD-2021-00011'
    label: cve@mitre.org
  - url: 'https://csirt.divd.nl/2021/07/07/Kaseya-Limited-Disclosure/'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://csrit.divd.nl/CVE-2021-30120'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://csrit.divd.nl/DIVD-2021-00011'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
  - in-the-wild
epss: 0.05701
epssPercentile: 0.92734
exploited: true
ingestedAt: '2026-08-14T06:15:27.658Z'
---

## Overview

Kaseya VSA before 9.5.7 allows attackers to bypass the 2FA requirement. The need to use 2FA for authentication in enforce client-side instead of server-side and can be bypassed using a local proxy. Thus rendering 2FA useless. Detailed description --- During the login process, after the user authenticates with username and password, the server sends a response to the client with the booleans MFARequired and MFAEnroled. If the attacker has obtained a password of a user and used an intercepting proxy (e.g. Burp Suite) to change the value of MFARequered from True to False, there is no prompt for the second factor, but the user is still logged in.

## Affected

- `vsa <= 9.5.6`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.