Brute force exploit can be used to collect valid usernames
Impact
A brute force exploit that can be used to collect valid usernames is possible.
Explanation of the vulnerability
It's a brute force exploit that can be used to collect valid usernames by using the “forgot password” function when trying to log into the Backoffice. If the username/email is known, it is easier to find the corresponding password. If an email address that was already used and registered by a user, is provided as an input, the server internal processing time takes longer. If the email address does not exist in the database of the registered users, the server would respond immediately.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| .NET (NuGet) | Umbraco.CMS | >= 8.0.0, < 8.18.10, >= 9.0.0, < 10.8.1, >= 11.0.0, < 12.3.4 | 8.18.10, 10.8.1, 12.3.4 |
References
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:N- Weakness (CWE)
CWE-200- Platform
- .NET (NuGet)
- Package
Umbraco.CMS- Disclosed
- 13.12.2023
- Updated
- 11.10.2026 11:23
Sources and licenses
OSV / GitHub Advisory Database - GHSA-7x74-h8cw-qhxq - CC BY 4.0
Vulnerability history: Umbraco.CMS
All published vulnerabilities of this package (.NET (NuGet)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 29
- First → latest
- 05.2022 09.2026
- Without a fix
- 1
- Exploited in attacks
- 0
Severity breakdown
- High 5
- Medium 17
- Low 7
Disclosures per year
- 2022: 2
- 2023: 8
- 2024: 5
- 2025: 8
- 2026: 6
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Brute force exploit can be used to collect valid usernames this entry
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