PDF JavaScript execution via unfiltered media upload
Published Dec 22, 2025 · Updated Dec 22, 2025
Arbitrary file upload in Umbraco CMS 16.3.3 allows remote attackers to store a crafted PDF that executes JavaScript when opened. The media upload path accepts PDF content without built-in server-side content filtering, leaving validation to an optional implementation hook. Umbraco disputes that this is a product vulnerability because PDF JavaScript remains isolated from the site DOM; execution requires a user to open the uploaded document.
Summary
What happened
Arbitrary file upload in Umbraco CMS 16.3.3 allows remote attackers to store a crafted PDF that executes JavaScript when opened. The media upload path accepts PDF content without built-in server-side content filtering, leaving validation to an optional implementation hook. Umbraco disputes that this is a product vulnerability because PDF JavaScript remains isolated from the site DOM; execution requires a user to open the uploaded document.
The record
- CVE
- CVE-2025-67288
- Published
- Dec 22, 2025
- Updated
- Dec 22, 2025
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-434, CWE-79, T1204.002
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Dec 22, 2025CVE publishedPublication date reported by the CVE source.
- Dec 22, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
What conditions does exploitation require?
What is affected?
Affected products and versions are unavailable in this record.
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- success_xss.pdf proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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