LibreNMS Ports Stored Cross-site Scripting vulnerabilityGHSA-27vf-3g4f-6jp7
MEDIUMFix: librenms/librenms#16721GHSA-27vf-3g4f-6jp7 is a medium-severity (CVSS 4.6) Cross-site Scripting (XSS) vulnerability in librenms/librenms. A fix is available for librenms/librenms — see the affected versions and patch details below.
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-27vf-3g4f-6jp7.
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
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
StoredXSS-LibreNMS-Ports
Description:
Stored XSS on the parameter:
/ajax_form.php -> param: descr
Request:
POST /ajax_form.php HTTP/1.1
Host: <your_host>
X-Requested-With: XMLHttpRequest
X-CSRF-TOKEN: <your_XSRF_token>
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
Cookie: <your_cookie>
type=update-ifalias&descr=%22%3E%3Cimg+src+onerror%3D%22alert(1)%22%3E&ifName=lo&port_id=1&device_id=1
of Librenms version 24.10.1 (https://github.com/librenms/librenms) allows remote attackers to inject malicious scripts. When a user views or interacts with the page displaying the data, the malicious script executes immediately, leading to potential unauthorized actions or data exposure.
Proof of Concept:
- Add a new device through the LibreNMS interface.
- Edit the newly created device and select the "ports" section.
- In the "Description" field, enter the following payload:
"><img src onerror="alert(1)">. - Save the changes.
- The XSS vulnerability is triggered when accessing the "ports" tab, and the payload is executed again when hovering over the modified value in the "Port" field.
Payload:
Executes:
The script execution vulnerability in the description field, as shown in the image, occurs at Line 63 of functions.inc.php
$overlib_content = '<div class=overlib><span class=overlib-text>' . $text . '</span><br />';
Impact:
Execution of Malicious Code
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | librenms/librenms | all versions | 24.11.0composer require librenms/librenms:^24.11.0 |
Affected Products
librenmslibrenmsDetection & 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 24.11.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-27vf-3g4f-6jp7 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.
Frequently Asked Questions
Is GHSA-27vf-3g4f-6jp7 in your dependencies?
Find it across Packagist, including transitive dependencies.