---
id: "CVE-2021-36742"
kind: "vulnerability"
aliases: ["CVE-2021-36742"]
title: "Trend Micro Apex One, Apex One as a Service, and Worry-Free Business Security: Trend Micro Multiple Products Improper Input Validation Vulnerability"
severity: "high"
cvss: 7.8
epss: 0.01482
exploited: true
status: "open"
category: "vendor"
products: [{"name": "Trend Micro Apex One, Apex One as a Service, and Worry-Free Business Security", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["apex-one", "exploited", "self-hosted", "trend-micro", "vendor", "windows", "worry-free-business-security"]
not_affected_if: ["managed-hosting", "no-local-low-privilege-access"]
published_at: "2021-07-29T20:15:07+00:00"
first_seen_at: "2026-10-23T19:11:53+00:00"
updated_at: "2026-10-23T20:29:39+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-36742", "first_seen_at": "2026-10-23T19:11:53+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2021-36742", "first_seen_at": "2026-10-23T19:13:43+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-36742", "first_seen_at": "2026-10-23T19:35:23+00:00"}]
---

# Trend Micro Apex One, Apex One as a Service, and Worry-Free Business Security: Trend Micro Multiple Products Improper Input Validation Vulnerability

Trend Micro Apex One, Apex One as a Service, OfficeScan XG and Worry-Free Business Security 10.0 SP1 have an improper input validation flaw. A local attacker who already runs low-privileged code on the machine can escalate to higher privileges.

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

## Affected

- vendor:Trend Micro Apex One, Apex One as a Service, and Worry-Free Business Security affected ? fixed ?

## Timeline

- 2026-10-23T19:11:53+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-36742
- 2026-10-23T19:13:43+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2021-36742
- 2026-10-23T19:35:23+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2021-36742

## From the sources

A improper input validation vulnerability in Trend Micro Apex One, Apex One as a Service, OfficeScan XG and Worry-Free Business Security 10.0 SP1 allows a local attacker to escalate privileges on affected installations. Please note: an attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability.

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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_