CVE-2023-49278
Umbraco CMS brute force exploit can be used to collect valid usernames
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- Low
- Integrity
- None
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Umbraco CMS brute force exploit can be used to collect valid usernames
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.
- Record
CVE-2023-49278- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N - Weakness
- CWE-200, CWE-307
- Updated
- 2026-11-02
EUVDEUVD-2023-3155
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.
- Record
EUVD-2023-3155- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-7x74-h8cw-qhxq
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.
- Record
GHSA-7x74-h8cw-qhxq- CVSS 3.1
- 0.0 None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:N - Weakness
- CWE-200
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2023-49278- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N - Weakness
- CWE-200, CWE-307
- Updated
- 2026-11-02
OSV
Umbraco CMS brute force exploit can be used to collect valid usernames
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.
- Record
CVE-2023-49278- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N - Weakness
- CWE-200, CWE-307
- Updated
- 2026-11-02
OSVGHSA-7x74-h8cw-qhxq
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.
- Record
GHSA-7x74-h8cw-qhxq- CVSS 3.1
- 0.0 None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:N - Weakness
- CWE-200
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
Umbraco.CMSNuGet |
8.0.0 up to 8.18.10 | 8.18.10 |
Umbraco.CMSNuGet |
9.0.0 up to 10.8.1 | 10.8.1 |
Umbraco.CMSNuGet |
11.0.0 up to 12.3.4 | 12.3.4 |
Umbraco.CMSNuGet |
9.0.0 up to 10.8.1, plus listed versions 10.0.010.0.0-rc110.0.0-rc210.0.0-rc310.0.0-rc4 Show 45 moreShow less10.0.0-rc510.0.110.1.010.1.0-rc10.1.0-rc210.1.110.2.010.2.0-rc10.2.110.3.010.3.0-rc10.3.110.3.210.4.010.4.0-rc10.4.110.4.210.5.010.5.0-rc10.5.110.6.010.6.0-rc10.6.110.7.010.7.0-rc10.8.010.8.0-rc9.0.19.1.09.1.0-rc9.1.19.1.29.2.09.2.0-rc9.3.09.3.0-rc9.3.19.4.09.4.0-rc9.4.19.4.29.4.39.5.09.5.0-rc9.5.0-rc2 |
10.8.1 |
Umbraco.CMSNuGet |
11.0.0 up to 12.3.4, plus listed versions 11.1.011.1.0-rc11.2.011.2.0-rc11.2.1 Show 28 moreShow less11.2.211.3.011.3.0-rc11.3.111.4.011.4.0-rc11.4.111.4.211.5.011.5.0-rc12.0.012.0.0-rc112.0.0-rc212.0.0-rc312.0.0-rc412.0.0-rc512.0.112.1.012.1.0-rc12.1.112.1.212.2.012.2.0-rc12.3.012.3.0-rc12.3.112.3.212.3.3 |
12.3.4 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases, published | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2023-49278 is a medium vulnerability (CVSS 5.3) in Umbraco Cms, published December 12, 2023. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.50%, the 43rd percentile. Fixed in Umbraco.CMS 8.18.10.
References
Left out here: 5 versions. The JSON record has them.