# CVE-2021-40113: Cisco Catalyst PON Series Switches Optical Network Terminal Vulnerabilities

> Unauthenticated attackers can execute arbitrary commands and modify configurations on Cisco Catalyst PON switches if Telnet is enabled.

- **Severity:** Critical 10.0 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 4 Nov 2021
- **Updated:** 7 Nov 2024
- **Also known as:** GHSA-gf95-pcww-8h2h

## What is CVE-2021-40113?

CVE-2021-40113 is a critical command injection vulnerability in Cisco Catalyst PON Series, published on 4 Nov 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Multiple vulnerabilities in the web-based management interface of the Cisco Catalyst Passive Optical Network (PON) Series Switches Optical Network Terminal (ONT) could allow an unauthenticated, remote attacker to perform the following actions: Log in with a default credential if the Telnet protocol is enabled Perform command injection Modify the configuration For more information about these vulnerabilities, see the Details section of this advisory.

Weakness: CWE-78 (Improper Neutralization of Special Elements used in an OS Command), CWE-284 (Improper Access Control)

## Which versions are affected by CVE-2021-40113?

It affects 5 products.


Products: Cisco Catalyst Pon Switch Cgp-Ont-1p Firmware, Cisco Catalyst Pon Switch Cgp-Ont-4p Firmware, Cisco Catalyst Pon Switch Cgp-Ont-4pv Firmware, Cisco Catalyst Pon Switch Cgp-Ont-4pvc Firmware, Cisco Catalyst Pon Switch Cgp-Ont-4tvcw Firmware.

## How do I fix CVE-2021-40113?

No fix has been published for CVE-2021-40113 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-40113 being exploited?

There is no known exploitation of CVE-2021-40113 in the wild and no public exploit code.

Public exploit code:

- Multiple vulnerabilities in the web-based management interface of the Cisco Catalyst Passive Optical Network (PON) Series Switches Optical Network Terminal (ONT) could allow an unauthenticated, remote attacker to perform the following actions: Log in with a default credential if the Telnet protocol is enabled Perform c CVE project by @Sn0wAlice (github_poc): https://github.com/karamMahmad/CVE-2021-40113

## Other vulnerabilities in Cisco Catalyst PON Series

- [CVE-2021-34795](https://insights.sbomify.com/CVE-2021-34795/): Cisco Catalyst PON Series Switches Optical Network Terminal Vulnerabilities (critical 10.0)
- [CVE-2021-40112](https://insights.sbomify.com/CVE-2021-40112/): Cisco Catalyst PON Series Switches Optical Network Terminal Vulnerabilities (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-40113 and fix it if it is affected.

What it is: CVE-2021-40113 is a critical command injection vulnerability in Cisco Catalyst PON Series, published on 4 Nov 2021. 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-2021-40113 in the wild and no public exploit code.

Affected product: Cisco Catalyst PON Series. 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-2021-40113/ (Markdown: https://insights.sbomify.com/CVE-2021-40113/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-40113
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-40113
- OSV: https://osv.dev/vulnerability/CVE-2021-40113

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-40113/
Summaries are generated and may contain mistakes; the official description above is the record.