# CVE-2021-42011: Privilege escalation in Trend Micro Apex One

> A local attacker with low-privileged code execution can load a DLL with escalated privileges in Trend Micro Apex One.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 21 Oct 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-9rm3-vhw2-wcx7

## What is CVE-2021-42011?

CVE-2021-42011 is a high-severity vulnerability in Trendmicro Apex One, published on 21 Oct 2021. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

An incorrect permission assignment vulnerability in Trend Micro Apex One and Apex One as a Service could allow a local attacker to load a DLL with escalated 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.

Weakness: CWE-276 (Incorrect Default Permissions)

## Which versions are affected by CVE-2021-42011?

It affects 1 product.


Products: Trendmicro Apex One.

## How do I fix CVE-2021-42011?

No fix has been published for CVE-2021-42011 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-42011 being exploited?

There is no known exploitation of CVE-2021-42011 in the wild and no public exploit code.

## Other vulnerabilities in Trendmicro Apex One

- [CVE-2020-8599](https://insights.sbomify.com/CVE-2020-8599/): Trend Micro Apex One and OfficeScan Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2025-54948](https://insights.sbomify.com/CVE-2025-54948/): Trend Micro Apex One OS Command Injection (critical 9.4, exploited in the wild)
- [CVE-2021-36741](https://insights.sbomify.com/CVE-2021-36741/): Trend Micro Multiple Products Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2020-8467](https://insights.sbomify.com/CVE-2020-8467/): Trend Micro Apex One and OfficeScan Remote Code Execution (high 8.8, exploited in the wild)
- [CVE-2020-8468](https://insights.sbomify.com/CVE-2020-8468/): Trend Micro Multiple Products Content Validation Escape (high 8.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-42011 and fix it if it is affected.

What it is: CVE-2021-42011 is a high-severity vulnerability in Trendmicro Apex One, published on 21 Oct 2021. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-42011 in the wild and no public exploit code.

Affected product: Trendmicro Apex One. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2021-42011/ (Markdown: https://insights.sbomify.com/CVE-2021-42011/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-42011
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-42011
- OSV: https://osv.dev/vulnerability/CVE-2021-42011

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-42011/
Summaries are generated and may contain mistakes; the official description above is the record.