CVE-2025-59535 is a medium-severity (CVSS 6.5) Improper Input Validation vulnerability in DotNetNuke.Core. A fix is available for DotNetNuke.Core — see the affected versions and patch details below.
DotNetNuke.Core allows loading of unused themes on anonymous clients through query parameters
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-59535.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
DotNetNuke.CoreReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects NuGet packages — download data is not available via public APIs for these ecosystems.
Description
Summary
Arbitrary themes can be loaded through query parameters. If an installed theme had a vulnerability, even if it was not used on any page, this could be loaded on unsuspecting clients without knowledge of the site owner.
Details
Many people who run DNN sites have a number of installed themes that they do not actually use. This could be because they were testing many themes during initial setup, because they have changed themes over time, or because they have development and production versions of a theme. Whatever the reason, many times the unused themes will become outdated over time as site admins wouldn't have reason to update something that is not used. However, this could introduce an entry point to exploit a vulnerable theme by making the server run the unused theme for unsuspecting client requests. Depending on the vulnerability in a theme, this could lead to server side or client side arbitrary code execution. With DNN 10.1.0 this functionality is now disabled by default but a setting was introduced in the Security module to turn activate the functionality.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | DotNetNuke.Core | all versions | 10.1.0dotnet add package DotNetNuke.Core --version 10.1.0 |
Affected Products
dotnetnukednnsoftwareDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for DotNetNuke.Core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update DotNetNuke.Core to 10.1.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-59535 is resolved across your whole dependency graph.
Workarounds
Assume what was exposed is already known: rotate any credential, token or key that the affected component could return, restrict the endpoint to callers that genuinely need it, and strip sensitive fields from responses and error output at the boundary rather than relying on the client not to read them.
Frequently Asked Questions
Is CVE-2025-59535 in your dependencies?
Find it across NuGet, including transitive dependencies.