# CVE-2020-29379: Auth bypass in n/a

> Attackers can gain unauthenticated root shell access via Telnet during firmware updates on V-SOL OLT devices, leading to full system compromise.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N`)
- **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:** 29 Nov 2020
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-w4p5-jc3g-29j3

## What is CVE-2020-29379?

CVE-2020-29379 is a medium-severity authentication bypass vulnerability in n/a, published on 29 Nov 2020. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

An issue was discovered on V-SOL V1600D4L V1.01.49 and V1600D-MINI V1.01.48 OLT devices. During the process of updating the firmware, the update script starts a telnetd -l /bin/sh process that does not require authentication for TELNET access.

Weakness: CWE-306 (Missing Authentication for Critical Functionality)

## Which versions are affected by CVE-2020-29379?

It affects 2 products.


Products: Vsolcn V1600d-Mini Firmware, Vsolcn V1600d4l Firmware.

## How do I fix CVE-2020-29379?

No fix has been published for CVE-2020-29379 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-29379 being exploited?

There is no known exploitation of CVE-2020-29379 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2020-29376](https://insights.sbomify.com/CVE-2020-29376/): Hardcoded credentials in n/a (critical 9.8)
- [CVE-2020-29381](https://insights.sbomify.com/CVE-2020-29381/): Command injection in n/a (critical 9.8)
- [CVE-2020-29375](https://insights.sbomify.com/CVE-2020-29375/): Hardcoded credentials in n/a (high 8.8)
- [CVE-2020-29378](https://insights.sbomify.com/CVE-2020-29378/): Hardcoded credentials in n/a (high 8.8)
- [CVE-2020-29383](https://insights.sbomify.com/CVE-2020-29383/): Hardcoded credentials in n/a (high 7.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-29379 and fix it if it is affected.

What it is: CVE-2020-29379 is a medium-severity authentication bypass vulnerability in n/a, published on 29 Nov 2020. 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-2020-29379 in the wild and no public exploit code.

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-2020-29379/ (Markdown: https://insights.sbomify.com/CVE-2020-29379/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-29379
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-29379
- OSV: https://osv.dev/vulnerability/CVE-2020-29379

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-29379/
Summaries are generated and may contain mistakes; the official description above is the record.