SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2021-30120

Kaseya VSA before 9.5.7 allows attackers to bypass the 2FA requirement.

HIGH 7.5EPSS 5.70%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (5.70%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

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.

CVSS 3.1
7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
EPSS
5.70% probability · 93th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-669
Affected
kaseya/vsa
Source
cve@mitre.org
EPSS trend
0%5%10%26 October 2026: 5.70%26 October 202626 October 2026

EPSS 5.7% since 26 October 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.