# CVE-2021-23241: Path traversal in n/a

> Attackers can bypass authentication and read arbitrary files on MERCUSYS Mercury X18G routers via directory traversal in web URIs.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 7 Jan 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-7crf-438p-2fw4

## What is CVE-2021-23241?

CVE-2021-23241 is a medium-severity path traversal vulnerability in n/a, published on 7 Jan 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

MERCUSYS Mercury X18G 1.0.5 devices allow Directory Traversal via ../ in conjunction with a loginLess or login.htm URI (for authentication bypass) to the web server, as demonstrated by the /loginLess/../../etc/passwd URI.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2021-23241?

It affects 1 product.


Products: Mercusys Mercury X18g Firmware.

## How do I fix CVE-2021-23241?

No fix has been published for CVE-2021-23241 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-23241 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-23241 exists.

Public exploit code:

- MERCUSYS Mercury X18G 1.0.5 Router - Local File Inclusion (nuclei): http/cves/2021/CVE-2021-23241.yaml

## Other vulnerabilities in n/a

- [CVE-2021-25811](https://insights.sbomify.com/CVE-2021-25811/): Denial of service in n/a (high 7.5)
- [CVE-2021-25810](https://insights.sbomify.com/CVE-2021-25810/): Cross-site scripting in n/a (medium 6.1)
- [CVE-2021-23242](https://insights.sbomify.com/CVE-2021-23242/): Path traversal in n/a (medium 5.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-23241 and fix it if it is affected.

What it is: CVE-2021-23241 is a medium-severity path traversal vulnerability in n/a, published on 7 Jan 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-23241 exists.

Affected product: n/a. 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-2021-23241/ (Markdown: https://insights.sbomify.com/CVE-2021-23241/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-23241
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-23241
- OSV: https://osv.dev/vulnerability/CVE-2021-23241

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-23241/
Summaries are generated and may contain mistakes; the official description above is the record.