GHSA-frc6-pwgr-c28w
MEDIUMLibreNMS has a Stored XSS vulnerability in its Alert Transport name field
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
LibreNMS <= 25.8.0 contains a Stored Cross-Site Scripting (XSS) vulnerability in the Alert Transports management functionality. When an administrator creates a new Alert Transport, the value of the Transport name field is stored and later rendered in the Transports column of the Alert Rules page without proper input validation or output encoding. This leads to arbitrary JavaScript execution in the admin’s browser.
Details
- Injection point:
Transport namefield in/alert-transports. - Execution point: Transports column in
/alert-rules. - Scope: Only administrators can create Alert Transports, and only administrators can view the affected Alert Rules page. Therefore, both exploitation and impact are limited to admin users.
Steps to reproduce
-
Log in with an administrator account.
-
Navigate to:
http://localhost:8000/alert-transports -
Click Create alert transport and provide the following values:
-
Transport name:
'onfocus='alert(1)' autofocus= -
Default Alert:
ON -
Email:
[email protected](or any valid email)
Save the transport.
-
-
Navigate to
<img width="1829" height="396" alt="image" src="https://github.com/user-attachments/assets/932ba17d-214d-4253-80b8-62539d1cfa28" />http://localhost:8000/alert-rules. A popupalert(1)is triggered, confirming that the payload executes.
Impact
Only accounts with the admin role who access the Alert Rules page (http://localhost:8000/alert-rules) are affected.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | librenms/librenms | all versions | 25.10.0 |
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 25.10.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-frc6-pwgr-c28w 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-frc6-pwgr-c28w 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-frc6-pwgr-c28w. 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-frc6-pwgr-c28w in your dependencies?
O3 detects GHSA-frc6-pwgr-c28w across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.