# CVE-2023-49278: Umbraco CMS brute force exploit can be used to collect valid usernames

> Attackers can brute force valid usernames in Umbraco CMS, exposing user account information.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 12 Dec 2023
- **Updated:** 8 Oct 2024
- **Also known as:** GHSA-7x74-h8cw-qhxq

## What is CVE-2023-49278?

CVE-2023-49278 is a medium-severity vulnerability in Umbraco Umbraco Cms, published on 12 Dec 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Umbraco is an ASP.NET content management system (CMS). Starting in version 8.0.0 and prior to versions 8.18.10, 10.8.1, and 12.3.4, a brute force exploit can be used to collect valid usernames. Versions 8.18.10, 10.8.1, and 12.3.4 contain a patch for this issue.

Weakness: CWE-307 (Improper Restriction of Excessive Authentication Attempts), CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor)

## Which versions are affected by CVE-2023-49278?

6 open source packages ship an affected version, including Umbraco.CMS. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `Umbraco.CMS` | NuGet | From 11.0.0 | 12.3.4 |
| `Umbraco.CMS` | NuGet | From 11.0.0 | 12.3.4 |
| `Umbraco.CMS` | NuGet | From 8.0.0 | 8.18.10 |
| `Umbraco.CMS` | NuGet | From 8.0.0 | 8.18.10 |
| `Umbraco.CMS` | NuGet | From 9.0.0 | 10.8.1 |
| `Umbraco.CMS` | NuGet | From 9.0.0 | 10.8.1 |

Products: Umbraco Umbraco Cms.

## How do I fix CVE-2023-49278?

Upgrade Umbraco.CMS to a fixed version for your release line: 12.3.4, 8.18.10 or 10.8.1.

## Is CVE-2023-49278 being exploited?

There is no known exploitation of CVE-2023-49278 in the wild and no public exploit code.

## Other vulnerabilities in Umbraco Umbraco Cms

- [CVE-2025-67288](https://insights.sbomify.com/CVE-2025-67288/): Umbraco CMS has an arbitrary file upload vulnerability (critical 10.0)
- [CVE-2014-10074](https://insights.sbomify.com/CVE-2014-10074/): File upload in n/a (critical 9.8)
- [CVE-2012-1301](https://insights.sbomify.com/CVE-2012-1301/): Server-side request forgery in n/a (critical 9.8)
- [CVE-2012-10054](https://insights.sbomify.com/CVE-2012-10054/): Umbraco CMS < 4.7.1 codeEditorSave.asmx RCE (critical 9.3)
- [CVE-2025-32017](https://insights.sbomify.com/CVE-2025-32017/): Umbraco has a Management API Vulnerability to Path Traversal With Authenticated Users (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-49278 and fix it if it is affected.

What it is: CVE-2023-49278 is a medium-severity vulnerability in Umbraco Umbraco Cms, published on 12 Dec 2023. 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-2023-49278 in the wild and no public exploit code.

Affected packages and fixed versions:
- Umbraco.CMS (NuGet): affected from 11.0.0; fixed in 12.3.4
- Umbraco.CMS (NuGet): affected from 11.0.0; fixed in 12.3.4
- Umbraco.CMS (NuGet): affected from 8.0.0; fixed in 8.18.10
- Umbraco.CMS (NuGet): affected from 8.0.0; fixed in 8.18.10
- Umbraco.CMS (NuGet): affected from 9.0.0; fixed in 10.8.1
- Umbraco.CMS (NuGet): affected from 9.0.0; fixed in 10.8.1

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-2023-49278/ (Markdown: https://insights.sbomify.com/CVE-2023-49278/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-49278
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-49278
- OSV: https://osv.dev/vulnerability/CVE-2023-49278

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-49278/
Summaries are generated and may contain mistakes; the official description above is the record.