Stored XSS via unsanitized SVG upload
Published Apr 17, 2026 · Updated Apr 17, 2026
Stored XSS in DNN Platform before 10.2.2 allows remote authenticated users to execute JavaScript in another user's browser via SVG upload. The upload path accepts and stores an SVG whose anchor contains a javascript: URL, then serves the file without neutralizing that active content. Exploitation requires upload access and two victim clicks; a power-user victim lets the script abuse UpdateConfigFile to write an ASPX backdoor.
Summary
What happened
Stored XSS in DNN Platform before 10.2.2 allows remote authenticated users to execute JavaScript in another user's browser via SVG upload. The upload path accepts and stores an SVG whose anchor contains a javascript: URL, then serves the file without neutralizing that active content. Exploitation requires upload access and two victim clicks; a power-user victim lets the script abuse UpdateConfigFile to write an ASPX backdoor.
The record
- CVE
- CVE-2026-40321
- Published
- Apr 17, 2026
- Updated
- Apr 17, 2026
- Vendor
- DNN Software
- Product
- DNN Platform
- Classifications
- CWE-87, CAPEC-199, T1059.007
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Apr 17, 2026CVE publishedPublication date reported by the CVE source.
- Apr 17, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 10.2.2
What conditions does exploitation require?
What is affected?
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
- DotNetNuke SVG XSS-to-RCE 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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