CVE-2025-48953
Umbraco Vulnerable to By-Pass of Configured Allowed Extensions for File Uploads
Umbraco is an ASP.NET content management system (CMS). Starting in version 14.0.0 and prior to versions 15.4.2 and 16.0.0, it's possible to upload a file that doesn't adhere with the configured allowable file extensions via a manipulated API request. The issue is patched in versions 15.4.2 and 16.0.0. No known workarounds are available.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- Low
- User interaction
- Required
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
Umbraco Vulnerable to By-Pass of Configured Allowed Extensions for File Uploads
Umbraco is an ASP.NET content management system (CMS). Starting in version 14.0.0 and prior to versions 15.4.2 and 16.0.0, it's possible to upload a file that doesn't adhere with the configured allowable file extensions via a manipulated API request. The issue is patched in versions 15.4.2 and 16.0.0. No known workarounds are available.
- Record
CVE-2025-48953- CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:L - Weakness
- CWE-434
- Updated
- 2026-11-02
EUVDEUVD-2025-16778
Umbraco is an ASP.NET content management system (CMS). Starting in version 14.0.0 and prior to versions 15.4.2 and 16.0.0, it's possible to upload a file that doesn't adhere with the configured allowable file extensions via a manipulated API request. The issue is patched in versions 15.4.2 and 16.0.0. No known workarounds are available.
- Record
EUVD-2025-16778- CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:L - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-fr6r-p8hv-x3c4
Umbraco Vulnerable to By-Pass of Configured Allowed Extensions for File Uploads
Impact
Via a manipulated API request it's possible to upload a file that doesn't adhere with the configured allowable file extensions.
Patches
Patched in 15.4.2 and 16.0.0.
Workarounds
None available.
- Record
GHSA-fr6r-p8hv-x3c4- CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:L - Weakness
- CWE-434
- Updated
- 2026-11-02
NVD
Umbraco is an ASP.NET content management system (CMS). Starting in version 14.0.0 and prior to versions 15.4.2 and 16.0.0, it's possible to upload a file that doesn't adhere with the configured allowable file extensions via a manipulated API request. The issue is patched in versions 15.4.2 and 16.0.0. No known workarounds are available.
- Record
CVE-2025-48953- CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:L - CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L - Weakness
- CWE-434
- Updated
- 2026-11-02
OSV
Umbraco Vulnerable to By-Pass of Configured Allowed Extensions for File Uploads
Umbraco is an ASP.NET content management system (CMS). Starting in version 14.0.0 and prior to versions 15.4.2 and 16.0.0, it's possible to upload a file that doesn't adhere with the configured allowable file extensions via a manipulated API request. The issue is patched in versions 15.4.2 and 16.0.0. No known workarounds are available.
- Record
CVE-2025-48953- CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:L - Weakness
- CWE-434
- Updated
- 2026-11-02
OSVGHSA-fr6r-p8hv-x3c4
Umbraco Vulnerable to By-Pass of Configured Allowed Extensions for File Uploads
Impact
Via a manipulated API request it's possible to upload a file that doesn't adhere with the configured allowable file extensions.
Patches
Patched in 15.4.2 and 16.0.0.
Workarounds
None available.
- Record
GHSA-fr6r-p8hv-x3c4- CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:L - Weakness
- CWE-434
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
Umbraco.CmsNuGet |
14.0.0 to 15.4.1 | 15.4.2 |
Umbraco.CmsNuGet |
14.0.0 up to 15.4.2, plus listed versions 14.1.014.1.0-rc14.1.0-rc214.1.114.1.2 Show 33 moreShow less14.2.014.2.0-rc14.2.0-rc214.2.0-rc314.3.014.3.0-rc14.3.114.3.214.3.314.3.415.0.015.0.0-rc115.0.0-rc215.0.0-rc315.0.0-rc415.1.015.1.0-rc15.1.0-rc215.1.115.1.215.2.015.2.0-rc15.2.115.2.215.2.315.3.015.3.0-rc15.3.0-rc215.3.115.4.015.4.0-rc15.4.0-rc215.4.1 |
15.4.2 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2025-48953 is a medium vulnerability (CVSS 5.5) in Umbraco Cms, published June 3, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.19%, the 9th percentile. Fixed in Umbraco.Cms 15.4.2.
References
github.com/umbraco/Umbraco-CMS/security/advisories/GHSA-fr6r-p8hv-x3c4
nvd.nist.gov/vuln/detail/CVE-2025-48953