CVE-2025-48953
Umbraco Vulnerable to By-Pass of Configured Allowed Extensions for File Uploads
No known exploitation. EPSS puts it in the 7th percentile. A vendor fix is available.
What to do
The vendor has published a fix. Version details are below where the sources state them.
What it is
From the CVE record
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.
In plain language
No plain-language summary for this CVE yet.
Exploitation
Where each signal puts this CVE on the scale from published to confirmed exploited.
- CISA KEV
Not in the catalog. CISA has not confirmed exploitation.
- Public exploits
No public exploit or proof of concept found in the sources we track.
- EPSS
0.2% chance of exploitation activity in the next 30 days, which ranks it in the 7th percentile of scored CVEs.
Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.
Lifecycle
5 events over 111 days, from the signal feeds we watch.
- Patch availablerecord updated
- Publishedweakness classified, att&ck mapped
Affected products
Technical detail
CVSS 3.1 vector
Open in the CVSS calculatorCVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:L
Scored 5.5 by NVD.
How it is reached
- Attack Vector NetworkExploitable remotely over the network without any special conditions
- Attack Complexity HighRequires specific conditions like a race condition or non-default configuration
- Privileges Required LowRequires basic user-level privileges
- User Interaction RequiredA user must click a link, open a file, or perform some action
Scope
- Scope ChangedThe exploit can affect other components (e.g. sandbox escape, host compromise from VM)
Impact if exploited
- Confidentiality LowSome restricted information is disclosed, but limited in scope
- Integrity LowData modification is possible but limited in scope or consequence
- Availability LowReduced performance or intermittent disruption of service
Weaknesses
ATT&CK techniques
Mapped from the weaknesses above (CWE to ATT&CK), not observed in attacks.
- Command and ControlT1105Ingress Tool Transferhigh confidence
- Initial AccessT1190Exploit Public-Facing Applicationhigh confidence
- PersistenceT1505Server Software Componenthigh confidence
Sources
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