CVE-2021-30120

9.9 CRITICAL 6% exploit odds Fix listed Auth & access Web app

What it is

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.

At a glance

Exploitability: Can be exploited over the network with a low-privilege account. High risk of data exposure, data tampering, service disruption.
Exploit odds: 5.7% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2021-04-02 00:00 UTC ReservedThe CVE id was reserved by its CNA
2021-07-09 14:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-08-14 05:16 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 5.7% in the next 30 days (EPSS).
Severity: 9.9 CRITICAL (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2021-07-09 14:15 UTC
Last modified: 2026-08-14 05:16 UTC
Exploit probability: 5.7% · EPSS, next 30 days
Weakness: CWE-669
Record status: Modified

Affected

Kaseya Vsa ≤ 9.5.6

Attack profile CVSS 3.1 · 9.9

Attack vector: Network
Complexity: Low
Privileges needed: Low
User interaction: None
Scope: Changed
Confidentiality: High
Integrity: High
Availability: High

Raw vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Is it in your code?

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Fix and advisories

References

NVD record · CVE.org record