---
id: "CVE-2018-20753"
kind: "vulnerability"
aliases: ["CVE-2018-20753"]
title: "Kaseya Virtual System/Server Administrator (VSA): Kaseya VSA Remote Code Execution Vulnerability"
severity: "critical"
cvss: 9.8
epss: 0.29551
exploited: true
status: "open"
category: "vendor"
products: [{"name": "Kaseya Virtual System/Server Administrator (VSA)", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["exploited", "kaseya-vsa", "msp", "ransomware", "rmm", "vendor"]
not_affected_if: ["not-running-kaseya-vsa"]
published_at: "2019-02-05T06:29:00+00:00"
first_seen_at: "2026-10-23T19:11:52+00:00"
updated_at: "2026-10-23T21:57:35+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2018-20753", "first_seen_at": "2026-10-23T19:11:52+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2018-20753", "first_seen_at": "2026-10-23T19:13:45+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2018-20753", "first_seen_at": "2026-10-23T21:57:35+00:00"}]
---

# Kaseya Virtual System/Server Administrator (VSA): Kaseya VSA Remote Code Execution Vulnerability

Kaseya VSA, a remote monitoring and management server, has a flaw that lets unauthenticated remote attackers run PowerShell payloads on every managed device. Attackers get code execution across the whole fleet of endpoints the server manages, and the flaw is known to be exploited, including in ransomware campaigns.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:Kaseya Virtual System/Server Administrator (VSA) affected ? fixed ?

## Fix

Apply the Kaseya-provided updates for VSA per vendor instructions (CISA required action); the specific fixed version is unknown from the sources.

## Timeline

- 2026-10-23T19:11:52+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2018-20753
- 2026-10-23T19:13:45+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2018-20753
- 2026-10-23T21:57:35+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2018-20753

## From the sources

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.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_