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Fencer Intel
medium 6.5

CVE-2021-30121 json

(Semi-)Authenticated local file inclusion in Kaseya VSA < v9.5.6

published 5y ago modified 4mo ago also EUVD-2021-17061

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
5.0%
EPSS 5.0% chance of exploitation in 30 days, percentile 92%
public exploits
0
none known

Summary

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

Patch / fix

  • kaseya vsa 9.5.6

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Exploit prediction

4.96% chance of exploitation in the next 30 days, higher than 92% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • csirt.divd.nl https://csirt.divd.nl/CVE-2021-30121 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
NVD 2.0 4.0 AV:N/AC:L/Au:S/C:P/I:N/A:N

Classification

Weakness
  • CWE-829 Inclusion of Functionality from Untrusted Control Sphere

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.