CVE-2018-20753 Kaseya VSA Remote Code Execution Vulnerability
Kaseya VSA RMM allows unprivileged remote attackers to execute PowerShell payloads on all managed devices.
From the CISA KEV catalogue version 2026.11.06, with Cybergen analysis. Updated 6 Nov 2026.
Should You Worry?
- CISA confirmed exploitation in the wild and added it to the Known Exploited Vulnerabilities catalogue on 13 Apr 2022.
- CISA lists it as known to be used in ransomware campaigns.
- Rated Critical severity (CVSS 9.8, scored by CISA).
- It has been in the catalogue for 1,668 days. Systems still unpatched now have almost certainly been scanned for it.
What It Is
Kaseya VSA RMM before R9.3 9.3.0.35, R9.4 before 9.4.0.36, and R9.5 before 9.5.0.5 allows unprivileged remote attackers to execute PowerShell payloads on all managed devices. In January 2018, attackers actively exploited this vulnerability in the wild.
What To Do Now
- 1
Find it
Search your asset inventory and external attack surface for Kaseya Virtual System/Server Administrator (VSA). Include cloud images, appliances and anything a supplier runs for you.
Attack Surface Management - 2
- 3
Hunt for compromise
If an affected system was reachable before you patched, assume it may have been hit. Check logs, new accounts, web shells and outbound connections from the date of exposure.
Incident Response - 4
Prove it is fixed
Rescan or test the system after patching. Upgrades that fail silently and forgotten secondary instances are common.
Penetration Testing
Vendor Advisories
The Compliance Clock
General guidance, not legal advice. Your obligations depend on your sector, scope and jurisdiction.
Not Sure If You Are Exposed?
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