Umbraco CMS brute force exploit can be used to collect valid usernames
Priority LOW 31CWE-200Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Information disclosure, Security bypass
- Confidentiality · integrity · availability
- Low · None · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-200 and CWE-307.
Summary
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.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.005 43rd percentileScored 2026-11-07
Fix Fixed Umbraco-CMS (umbraco): 8.18.10, 10.8.1, 12.3.4Umbraco.CMS (NuGet): 8.18.10, 10.8.1, 12.3.4
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| umbraco | Umbraco-CMS | 8.0.0 to before 8.18.10; 9.0.0-rc001 to before 10.8.1; 11.0.0-rc1 to before 12.3.4 | 8.18.10, 10.8.1, 12.3.4 | Patch available | CNA |
| — | Umbraco.CMS (NuGet) | 8.0.0 to before 8.18.10 | 8.18.10 | Patch available | GHSA-7x74-h8cw-qhxq |
| — | Umbraco.CMS (NuGet) | 9.0.0 to before 10.8.1 | 10.8.1 | Patch available | GHSA-7x74-h8cw-qhxq |
| — | Umbraco.CMS (NuGet) | 11.0.0 to before 12.3.4 | 12.3.4 | Patch available | GHSA-7x74-h8cw-qhxq |
- Umbraco-CMS Vendorumbraco Affected 8.0.0 to before 8.18.10; 9.0.0-rc001 to before 10.8.1; 11.0.0-rc1 to before 12.3.4 Fixed in 8.18.10, 10.8.1, 12.3.4 Patch available CNA
- Umbraco.CMS (NuGet) Vendor— Affected 8.0.0 to before 8.18.10 Fixed in 8.18.10 Patch available GHSA-7x74-h8cw-qhxq
- Umbraco.CMS (NuGet) Vendor— Affected 9.0.0 to before 10.8.1 Fixed in 10.8.1 Patch available GHSA-7x74-h8cw-qhxq
- Umbraco.CMS (NuGet) Vendor— Affected 11.0.0 to before 12.3.4 Fixed in 12.3.4 Patch available GHSA-7x74-h8cw-qhxq
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:umbraco:umbraco_cms:*:*:*:*:*:*:*:* | 8.0.0 to before 8.18.10; 10.0.0 to before 10.8.1; 12.0.0 to before 12.3.4 | Vulnerable | umbraco |
- cpe:2.3:a:umbraco:umbraco_cms:*:*:*:*:*:*:*:* Versions 8.0.0 to before 8.18.10; 10.0.0 to before 10.8.1; 12.0.0 to before 12.3.4 Vulnerable ·umbraco
Remediation
- Fix · CNA Umbraco-CMS (umbraco) Fixed in 8.18.10, 10.8.1, 12.3.4
- Fix · GHSA-7x74-h8cw-qhxq Umbraco.CMS (NuGet) Fixed in 8.18.10 Advisory →
- Fix · GHSA-7x74-h8cw-qhxq Umbraco.CMS (NuGet) Fixed in 10.8.1 Advisory →
- Fix · GHSA-7x74-h8cw-qhxq Umbraco.CMS (NuGet) Fixed in 12.3.4 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2023-49278
- 2026-10-03 Alias added: GHSA-7x74-h8cw-qhxq
References
More Umbraco Cms vulnerabilities
- TI-2025-41183 An arbitrary file upload vulnerability in Umbraco CMS v16.3.3 allows attackers to execute… CVSS 3.1CRITICAL 10.0
- TI-2012-05477 Umbraco CMS < 4.7.1 codeEditorSave.asmx RCE CVSS 4.0CRITICAL 9.3
- TI-2021-22392 Umbraco v8.14.1 - 'baseUrl' SSRF CVSS 4.0MEDIUM 6.9
- TI-2024-36846 A stored cross-site scripting (XSS) vulnerability in Umbraco CMS v14.3.1 allows attackers… CVSS 3.1MEDIUM 6.5
- TI-2019-15240 Umbraco CMS 4.11.8 through 7.15.10, and 7.12.4, allows Remote Code Execution by… CVSS 3.1HIGH 7.2
- TI-2020-04738 Cross-site scripting in Umbraco CMS CVSS 3.1MEDIUM 5.4
Sources
- CVE-2023-49278 · CVE Program
- CVE-2023-49278 · NVD
- FIRST EPSS
- GHSA-7x74-h8cw-qhxq · GitHub Advisory Database · CC BY 4.0
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