# CVE-2021-40186: DNN CMS Server-Side Request Forgery (SSRF)

> Attackers can exploit SSRF in DNN CMS to make unauthorized network requests, potentially accessing internal systems or cloud metadata.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N`)
- **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:** 31 May 2022
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-7fc9-x7pv-7jmw

## What is CVE-2021-40186?

CVE-2021-40186 is a medium-severity server-side request forgery vulnerability in Dnnsoftware Dotnetnuke, published on 31 May 2022. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

The AppCheck research team identified a Server-Side Request Forgery (SSRF) vulnerability within the DNN CMS platform, formerly known as DotNetNuke. SSRF vulnerabilities allow the attacker to exploit the target system to make network requests on their behalf, allowing a range of possible attacks. In the most common scenario, the attacker exploits SSRF vulnerabilities to attack systems behind the firewall and access sensitive information from Cloud Provider metadata services.

Weakness: CWE-918 (Server-Side Request Forgery)

## Which versions are affected by CVE-2021-40186?

It affects 1 product.


Products: Dnnsoftware Dotnetnuke.

## How do I fix CVE-2021-40186?

No fix has been published for CVE-2021-40186 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-40186 being exploited?

There is no known exploitation of CVE-2021-40186 in the wild and no public exploit code.

## Other vulnerabilities in Dnnsoftware Dotnetnuke

- [CVE-2017-9822](https://insights.sbomify.com/CVE-2017-9822/): DotNetNuke (DNN) Remote Code Execution (high 8.8, exploited in the wild)
- [CVE-2018-15811](https://insights.sbomify.com/CVE-2018-15811/): DotNetNuke (DNN) Inadequate Encryption Strength (high 7.5, exploited in the wild)
- [CVE-2018-18325](https://insights.sbomify.com/CVE-2018-18325/): DotNetNuke (DNN) Inadequate Encryption Strength (high 7.5, exploited in the wild)
- [CVE-2025-64095](https://insights.sbomify.com/CVE-2025-64095/): DNN Insufficient Access Control - Image Upload allows for Site Content Overwrite (critical 10.0)
- [CVE-2006-3601](https://insights.sbomify.com/CVE-2006-3601/): Privilege escalation in n/a (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-40186 and fix it if it is affected.

What it is: CVE-2021-40186 is a medium-severity server-side request forgery vulnerability in Dnnsoftware Dotnetnuke, published on 31 May 2022. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-40186 in the wild and no public exploit code.

Affected product: Dnnsoftware Dotnetnuke. 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-2021-40186/ (Markdown: https://insights.sbomify.com/CVE-2021-40186/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-40186
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-40186
- OSV: https://osv.dev/vulnerability/CVE-2021-40186

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-40186/
Summaries are generated and may contain mistakes; the official description above is the record.