# CVE-2026-40306: DNN has same HostGUID for all new installs

> Attackers can exploit identical Host GUIDs in new DNN installations to bypass security controls or impersonate hosts.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 17 Apr 2026
- **Updated:** 20 Apr 2026
- **Also known as:** GHSA-2rhw-gw3f-477j

## What is CVE-2026-40306?

CVE-2026-40306 is a medium-severity vulnerability in Dnnsoftware Dotnetnuke, published on 17 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

DNN (formerly DotNetNuke) is an open-source web content management platform (CMS) in the Microsoft ecosystem. All new installations of DNN 10.x.x - 10.2.1 have the same Host GUID. This does not affect upgrades from 9.x.x. Version 10.2.2 patches the issue.

Weakness: CWE-330 (Use of Insufficiently Random Values)

## Which versions are affected by CVE-2026-40306?

2 open source packages ship an affected version, including DotNetNuke.Core. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `DotNetNuke.Core` | NuGet | From 10.0.0 | 10.2.2 |
| `DotNetNuke.Core` | NuGet | From 10.0.0 | 10.2.2 |

Products: Dnnsoftware Dotnetnuke.

## How do I fix CVE-2026-40306?

Upgrade DotNetNuke.Core to 10.2.2 or later.

## Is CVE-2026-40306 being exploited?

There is no known exploitation of CVE-2026-40306 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-2026-40306 and fix it if it is affected.

What it is: CVE-2026-40306 is a medium-severity vulnerability in Dnnsoftware Dotnetnuke, published on 17 Apr 2026. 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-2026-40306 in the wild and no public exploit code.

Affected packages and fixed versions:
- DotNetNuke.Core (NuGet): affected from 10.0.0; fixed in 10.2.2
- DotNetNuke.Core (NuGet): affected from 10.0.0; fixed in 10.2.2

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-2026-40306/ (Markdown: https://insights.sbomify.com/CVE-2026-40306/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-40306
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40306
- OSV: https://osv.dev/vulnerability/CVE-2026-40306

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-40306/
Summaries are generated and may contain mistakes; the official description above is the record.