# CVE-2020-5142: Cross-site scripting in SonicOS

> Remote unauthenticated attackers can execute arbitrary JavaScript in the SonicOS SSLVPN portal, potentially compromising user sessions.

- **Severity:** Medium 6.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 12 Oct 2020
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-mm23-cj9m-mh27

## What is CVE-2020-5142?

CVE-2020-5142 is a medium-severity cross-site scripting vulnerability in Sonicwall Sonicos, published on 12 Oct 2020. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

A stored cross-site scripting (XSS) vulnerability exists in the SonicOS SSLVPN web interface. A remote unauthenticated attacker is able to store and potentially execute arbitrary JavaScript code in the firewall SSLVPN portal. This vulnerability affected SonicOS Gen 5 version 5.9.1.7, 5.9.1.13, Gen 6 version 6.5.4.7, 6.5.1.12, 6.0.5.3, SonicOSv 6.5.4.v and Gen 7 version SonicOS 7.0.0.0.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2020-5142?

It affects 2 products.


Products: Sonicwall Sonicos, Sonicwall Sonicosv.

## How do I fix CVE-2020-5142?

No fix has been published for CVE-2020-5142 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-5142 being exploited?

There is no known exploitation of CVE-2020-5142 in the wild and no public exploit code.

Public exploit code:

- Reflected XSS found by Burp Suite in several locations on SonicOS 7.0 Sonicwall NSA device. (github_poc): https://github.com/hackerlawyer/CVE-2020-5142-POC-MB

## Other vulnerabilities in Sonicwall Sonicos

- [CVE-2020-5135](https://insights.sbomify.com/CVE-2020-5135/): SonicWall SonicOS Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2024-40766](https://insights.sbomify.com/CVE-2024-40766/): SonicWall SonicOS Improper Access Control (critical 9.3, exploited in the wild)
- [CVE-2024-53704](https://insights.sbomify.com/CVE-2024-53704/): SonicWall SonicOS SSLVPN Improper Authentication (high 8.2, exploited in the wild)
- [CVE-2025-40600](https://insights.sbomify.com/CVE-2025-40600/): Denial of service in SonicOS (critical 9.8)
- [CVE-2024-22394](https://insights.sbomify.com/CVE-2024-22394/): Auth bypass in SonicOS (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-5142 and fix it if it is affected.

What it is: CVE-2020-5142 is a medium-severity cross-site scripting vulnerability in Sonicwall Sonicos, published on 12 Oct 2020. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2020-5142 in the wild and no public exploit code.

Affected product: Sonicwall Sonicos. 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-2020-5142/ (Markdown: https://insights.sbomify.com/CVE-2020-5142/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-5142
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-5142
- OSV: https://osv.dev/vulnerability/CVE-2020-5142

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-5142/
Summaries are generated and may contain mistakes; the official description above is the record.