What is CVE-2021-30121?

CVE-2021-30121 is a medium-severity vulnerability in Kaseya Vsa, classified under Inclusion of Functionality from Untrusted Control Sphere. CVSS score: 6.5/10. Published 2021-07-09.

How severe is CVE-2021-30121?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Vulnerability in Kaseya Vsa

CVE-2021-30121

Semi-authenticated local file inclusion The contents of arbitrary files can be returned by the webserver Example request: `https://x.x.x.x/KLC/js/Kaseya.SB.JS/js.aspx?path=C:\Kaseya\WebPages\dl.asp` A valid sessionId is required but can be easily obtained via CVE-2021-30118

Published 2021-07-09 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.048 (91.6th percentile), scored 2026-09-23.

Low probability of exploitation in the next 30 days, but still tracked. 92nd percentile — 91.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.048 · newest: 0.048 · change: 0.000

Affected products

Kaseya Vsa

Weakness classification (CWE)

CWE-829 — Inclusion of Functionality from Untrusted Control Sphere

References

csirt.divd.nl/2021/07/07/Kaseya-Limited-Disclosure/ (Patch, Third Party Advisory)
csirt.divd.nl/DIVD-2021-00011 (Patch, Third Party Advisory)
csirt.divd.nl/CVE-2021-30121 (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2021-30121?: CVE-2021-30121 is a medium-severity vulnerability in Kaseya Vsa, classified under Inclusion of Functionality from Untrusted Control Sphere. CVSS score: 6.5/10. Published 2021-07-09.
How severe is CVE-2021-30121?: Medium severity. CVSS v3 base score is 6.5 out of 10.