# CVE-2021-43066: Privilege escalation in Fortinet FortiClientWindows

> An attacker can escalate privileges on Windows systems by exploiting improper file path control in the FortiClient MSI installer.

- **Severity:** High 8.4 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H/E:H/RL:U/RC:C`)
- **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:** 11 May 2022
- **Updated:** 22 Oct 2024
- **Also known as:** GHSA-726x-mfp5-rvmh

## What is CVE-2021-43066?

CVE-2021-43066 is a high-severity vulnerability in Fortinet Forticlient, published on 11 May 2022. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A external control of file name or path in Fortinet FortiClientWindows version 7.0.2 and below, version 6.4.6 and below, version 6.2.9 and below, version 6.0.10 and below allows attacker to escalate privilege via the MSI installer.

Weakness: CWE-668 (Exposure of Resource to Wrong Sphere)

## Which versions are affected by CVE-2021-43066?

It affects 1 product.


Products: Fortinet Forticlient.

## How do I fix CVE-2021-43066?

No fix has been published for CVE-2021-43066 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-43066 being exploited?

There is no known exploitation of CVE-2021-43066 in the wild and no public exploit code.

## Other vulnerabilities in Fortinet Forticlient

- [CVE-2019-17658](https://insights.sbomify.com/CVE-2019-17658/): Privilege escalation in Fortinet FortiClientWindows (critical 9.8)
- [CVE-2023-45590](https://insights.sbomify.com/CVE-2023-45590/): Code injection in FortiClientLinux (critical 9.4)
- [CVE-2017-14184](https://insights.sbomify.com/CVE-2017-14184/): Information disclosure in FortiClient SSLVPN Client for Linux (high 8.8)
- [CVE-2016-8493](https://insights.sbomify.com/CVE-2016-8493/): Privilege escalation in Fortinet FortiClient (high 8.8)
- [CVE-2020-15934](https://insights.sbomify.com/CVE-2020-15934/): Privilege escalation in FortiClientLinux (high 8.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-43066 and fix it if it is affected.

What it is: CVE-2021-43066 is a high-severity vulnerability in Fortinet Forticlient, published on 11 May 2022. 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-2021-43066 in the wild and no public exploit code.

Affected product: Fortinet Forticlient. 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-2021-43066/ (Markdown: https://insights.sbomify.com/CVE-2021-43066/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-43066
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-43066
- OSV: https://osv.dev/vulnerability/CVE-2021-43066

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-43066/
Summaries are generated and may contain mistakes; the official description above is the record.