GHSA-frc6-pwgr-c28w is a medium-severity (CVSS 5.5) Cross-site Scripting (XSS) vulnerability in librenms/librenms. EPSS puts its 30-day exploitation probability at 12.7% (96th percentile). A fix is available for librenms/librenms — see the affected versions and patch details below.
LibreNMS has a Stored XSS vulnerability in its Alert Transport name field
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for GHSA-frc6-pwgr-c28w.
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.
How urgent is this, really
GHSA-frc6-pwgr-c28w plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 379,145 CVEs with a current EPSS score, this one falls in the 10–50% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
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 | 25.10.0composer require librenms/librenms:^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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-frc6-pwgr-c28w can be triaged on real exposure rather than presence alone.
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 Security finds GHSA-frc6-pwgr-c28w across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.