GHSA-x8gm-j36p-fppf
MEDIUMLibreNMS vulnerable to Stored Cross-site Scripting via File Upload
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
librenms/librenmsReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
Summary
Stored Cross-Site Scripting (XSS) can archive via Uploading a new Background for a Custom Map.
Details
Users with "admin" role can set background for a custom map, this allow the upload of SVG file that can contain XSS payload which will trigger onload. This led to Stored Cross-Site Scripting (XSS).
PoC
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Login using an Admin role account.
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Go over to "$URL/maps/custom", the Manage Custom Maps.
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Create a new map then choose to edit it.
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Choose the "Set Background" option.
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Choose to upload a SVG file that have this content.
<svg xmlns="http://www.w3.org/2000/svg" onload="alert(document.domain)">
<circle cx="50" cy="50" r="40" />
</svg>
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Once uploaded, there should be a link to the SVG return in the POST request to the API "$URL/maps/custom/1/background".
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Go over to that link on browser, should see a pop-up.
Impact
Attacker can use this to perform malicious java script code for malicious intent. This would impact other Admin role users and the Global Read role users. Normal users does not have permission to read the file, so they are not affected.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | librenms/librenms | all versions | 24.9.0 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for librenms/librenms. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update librenms/librenms to 24.9.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-x8gm-j36p-fppf is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-x8gm-j36p-fppf is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-x8gm-j36p-fppf. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-x8gm-j36p-fppf in your dependencies?
O3 detects GHSA-x8gm-j36p-fppf across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.