# CVE-2020-5136: Memory corruption in SonicOS

> An authenticated attacker can trigger a buffer overflow in SonicOS, causing a firewall crash and denial of service.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 12 Oct 2020
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-85r9-8q36-5hm5

## What is CVE-2020-5136?

CVE-2020-5136 is a medium-severity memory corruption vulnerability in Sonicwall Sonicos, published on 12 Oct 2020. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A buffer overflow vulnerability in SonicOS allows an authenticated attacker to cause Denial of Service (DoS) in the SSL-VPN and virtual assist portal, which leads to a firewall crash. 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 7.0.0.0.

Weakness: CWE-120 (Buffer Copy without Checking Size of Input)

## Which versions are affected by CVE-2020-5136?

It affects 2 products.


Products: Sonicwall Sonicos, Sonicwall Sonicosv.

## How do I fix CVE-2020-5136?

No fix has been published for CVE-2020-5136 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-5136 being exploited?

There is no known exploitation of CVE-2020-5136 in the wild and no public exploit code.

## 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-2020-5136 and fix it if it is affected.

What it is: CVE-2020-5136 is a medium-severity memory corruption vulnerability in Sonicwall Sonicos, published on 12 Oct 2020. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2020-5136 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-2020-5136/ (Markdown: https://insights.sbomify.com/CVE-2020-5136/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-5136
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-5136
- OSV: https://osv.dev/vulnerability/CVE-2020-5136

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-5136/
Summaries are generated and may contain mistakes; the official description above is the record.