# CVE-2021-26102: Path traversal in FortiWAN

> Remote unauthenticated attackers can delete configuration files via path traversal, resetting the admin password to default and gaining control.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:H/RL:U/RC:C`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 19 Dec 2024
- **Updated:** 19 Dec 2024
- **Also known as:** GHSA-wwq6-xmjh-4f52

## What is CVE-2021-26102?

CVE-2021-26102 is a critical path traversal vulnerability in Fortinet FortiWAN, published on 19 Dec 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A relative path traversal vulnerability (CWE-23) in FortiWAN version 4.5.7 and below, 4.4 all versions may allow a remote non-authenticated attacker to delete files on the system by sending a crafted POST request. In particular, deleting specific configuration files will reset the Admin password to its default value.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory), CWE-305 (Authentication Bypass by Primary Weakness)

## Which versions are affected by CVE-2021-26102?

It affects 1 product.


Products: Fortinet Fortiwan.

## How do I fix CVE-2021-26102?

No fix has been published for CVE-2021-26102 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-26102 being exploited?

There is no known exploitation of CVE-2021-26102 in the wild and no public exploit code.

Public exploit code:

- PoC of FortiWAN auth bypass (https://www.fortiguard.com/psirt/FG-IR-21-048) (github_poc): https://github.com/SleepyCofe/CVE-2021-26102

## Other vulnerabilities in Fortinet FortiWAN

- [CVE-2021-26114](https://insights.sbomify.com/CVE-2021-26114/): SQL injection in Fortinet FortiWAN (critical 9.8)
- [CVE-2016-4965](https://insights.sbomify.com/CVE-2016-4965/): Command injection in n/a (high 8.8)
- [CVE-2023-44252](https://insights.sbomify.com/CVE-2023-44252/): Auth bypass in FortiWAN (high 8.6)
- [CVE-2023-44251](https://insights.sbomify.com/CVE-2023-44251/): Path traversal in FortiWAN (high 8.1)
- [CVE-2021-26112](https://insights.sbomify.com/CVE-2021-26112/): Memory corruption in Fortinet FortiWAN (high 8.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-26102 and fix it if it is affected.

What it is: CVE-2021-26102 is a critical path traversal vulnerability in Fortinet FortiWAN, published on 19 Dec 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-26102 in the wild and no public exploit code.

Affected product: Fortinet FortiWAN. 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-2021-26102/ (Markdown: https://insights.sbomify.com/CVE-2021-26102/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-26102
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-26102
- OSV: https://osv.dev/vulnerability/CVE-2021-26102

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-26102/
Summaries are generated and may contain mistakes; the official description above is the record.