CVE-2024-47526

A Self Cross-Site Scripting (Self-XSS) vulnerability in the "Alert Templates" feature allows users to inject arbitrary JavaScript into the alert template's name. This script executes immediately upon submission but does not persist after a page refresh.

Details

The vulnerability occurs when creating an alert template in the LibreNMS interface. Although the application sanitizes the "name" field when storing it in the database, this newly created template is immediately added to the table without any sanitization being applied to the name, allowing users to inject arbitrary JavaScript. This script executes when the template is created but does not persist in the database, thus preventing stored XSS.

For instance, the following payload can be used to exploit the vulnerability:
test1<script>{onerror=alert}throw 1337</script>

The root cause of this vulnerability lies in the lack of sanitization of the "name" variable before it is rendered in the table. The vulnerability exists because the bootgrid function of the jQuery grid plugin does not sanitize the text being added to the table. Although tags are stripped before being added to the database (as shown in the code below), the vulnerability still allows Self-XSS during the creation of the template.

Where the variable is being sanitized before being stored in the database:
https://github.com/librenms/librenms/blob/0e741e365aa974a74aee6b43d1b4b759158a5c7e/includes/html/forms/alert-templates.inc.php#L40

Where the vulnerability is happening:
https://github.com/librenms/librenms/blob/0e741e365aa974a74aee6b43d1b4b759158a5c7e/includes/html/modal/alert_template.inc.php#L205

PoC

1. Navigate to the "Alert Templates" creation page in the LibreNMS interface.
2. In the "Name" field, input the following payload:

test1<script>{onerror=alert}throw 1337</script>
3. Submit the form to create the alert template.
4. Observe that the JavaScript executes immediately, triggering an alert popup. However, this code does not persist after refreshing the page.

This is a Self Cross-Site Scripting (Self-XSS) vulnerability. Although the risk is lower compared to traditional XSS, it can still be exploited through social engineering or tricking users into entering or interacting with malicious code. This can lead to unauthorized actions or data exposure in the context of the affected user's session.

Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.

CVE-2024-47526 has a CVSS score of 3.5 (Low). The vector is network-reachable, high privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (24.9.0); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2024-47526? CVE-2024-47526 is a low-severity cross-site scripting (XSS) vulnerability in librenms/librenms (composer), affecting versions < 24.9.0. It is fixed in 24.9.0. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
2. How severe is CVE-2024-47526? CVE-2024-47526 has a CVSS score of 3.5 (Low). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of librenms/librenms are affected by CVE-2024-47526? librenms/librenms (composer) versions < 24.9.0 is affected.
4. Is there a fix for CVE-2024-47526? Yes. CVE-2024-47526 is fixed in 24.9.0. Upgrade to this version or later.
5. Is CVE-2024-47526 exploitable, and should I be worried? Whether CVE-2024-47526 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2024-47526 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2024-47526? Upgrade librenms/librenms to 24.9.0 or later.