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Fencer Vulns
medium 5.5

CVE-2025-48953 json

Umbraco Vulnerable to By-Pass of Configured Allowed Extensions for File Uploads

published 2025-06-03 17 mo ago modified 2026-06-17 4 mo ago also EUVD-2025-16778 , GHSA-fr6r-p8hv-x3c4

cvss
5.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 9%
public exploits
0
none known

Summary

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.

Patch / fix

  • nuget Umbraco.Cms 15.4.2
  • umbraco umbraco_cms 15.4.2

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
17 mo ago

Exploit prediction

0.19% chance of exploitation in the next 30 days, higher than 9% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.5 CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:L
GitHub 3.1 5.5 CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:L
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L

Affected packages

ecosystem package affected fixed in
nuget Umbraco.Cms
>=14.0.0, <15.4.2
15.4.2

Affected products

  • umbraco Umbraco-CMS

Classification

Weakness
  • CWE-434 Unrestricted Upload of File with Dangerous Type

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.