high CVSS 7.5 EPSS 0.59%

CVE-2024-47523·PHP vulnerability

LibreNMS is an open-source, PHP/MySQL/SNMP-based network monitoring system. A Stored Cross-Site Scripting (XSS) vulnerability in the "Alert Transports" feature allows authenticated users to inject arbitrary JavaScript through the "Details" section (which contains multiple fields depending on which transport is selected at that moment). This vulnerability can lead to the execution of malicious code in the context of other users' sessions, potentially compromising their accounts and allowing unauthorized actions. This vulnerability is fixed in 24.9.0.

Severity
high
Software
PHP
Fixed in
24.9.0
Published

How likely is exploitation

FIRST's Exploit Prediction Scoring System puts the probability of this CVE being exploited in the next 30 days at 0.59% — higher than 44% of all published CVEs. EPSS is an independent forecast of exploitation, not a severity rating: it says nothing about how much damage a successful attack does, which is what a CVSS score measures.

Read the two together. CVE-2024-47523 scores 7.5 on CVSS, so a successful attack would be serious — but at 0.59%, almost nobody is currently attempting it. That is a different situation from a flaw under mass exploitation, and it is usually the difference between patching on your next maintenance window and patching tonight.

Affected versions

Until: 24.9.0

Fixed in: 24.9.0

How to fix this CVE

LibreNMS administrators must upgrade to version 24.9.0 or later to patch a stored XSS vulnerability in the Alert Transports feature that allows authenticated users to inject malicious scripts through transport configuration fields. The vulnerability can be exploited to execute arbitrary JavaScript in other users' browsers, potentially leading to account compromise. Apply the update immediately to all affected LibreNMS instances.

sudo dnf upgrade php

Defensia detects this vulnerability

What an exploitation attempt looks like

Sample log line indicative of exploitation attempts:

POST /librenms/includes/html/print-alert-transports.php with parameters containing script tags, javascript: protocol, or event handlers (e.g., onerror=, onclick=) in the Details or transport configuration fields; log pattern: POST.*print-alert-transports\.php.*\b(script|javascript:|on\w+\s*=)

WAF mitigation (if patching is not yet possible)

Add this rule to your WAF to block exploitation attempts while you schedule the patch. 

Configure WAF rules to block POST requests to print-alert-transports.php containing JavaScript event handlers or script tags in request body parameters; implement Content Security Policy (CSP) headers with script-src 'self' to prevent inline script execution; sanitize all user input in transport detail fields server-side using HTML entity encoding before storage and display.

How to check if you are affected

  1. Check LibreNMS version: curl -s http://localhost/librenms/ | grep -i 'version' or check the .git/config if running from source
  2. Verify if Alert Transports feature is in use: Log into LibreNMS admin panel and navigate to Alerts → Alert Transports to see if any transports are configured
  3. Search web server logs for suspicious POST requests to print-alert-transports.php: grep -r 'print-alert-transports.php' /var/log/apache2/ /var/log/nginx/ containing encoded script tags or javascript: protocol
  4. Confirm the patch by checking the commit hash in the LibreNMS installation: git log --oneline | grep ee1afba or verify version string shows 24.9.0+

FAQ

What is CVE-2024-47523?

This is a stored cross-site scripting (XSS) flaw in LibreNMS's Alert Transports configuration interface that permits authenticated users to embed malicious JavaScript code in transport detail fields, which executes when other administrators view the affected transport settings.

Is CVE-2024-47523 being actively exploited?

No, this vulnerability is not currently listed in the CISA Known Exploited Vulnerabilities (KEV) catalog and no public exploits are available, though the vulnerability should still be patched promptly due to its high severity score and account compromise potential.

What versions of LibreNMS are affected by CVE-2024-47523?

All versions prior to LibreNMS 24.9.0 are vulnerable; the exact earliest affected version is unknown but the vulnerability affects the Alert Transports feature across the codebase history.

How do I check if my server is vulnerable to CVE-2024-47523?

Run `curl -s http://your-librenms-host/librenms/ | grep -oP '(?<=Version\s)[\d.]+' | head -1` to retrieve your current version; if it is below 24.9.0, your system is vulnerable.

Does Defensia detect CVE-2024-47523?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If LibreNMS is installed on a monitored server, CVE-2024-47523 will appear in your dashboard with remediation steps.

Related PHP CVEs

CVE-2026-39337CVSS 10ChurchCRM is an open-source church management system. Prior to 7.1.0, critical pre-authentication remote code execution vulnerability in ChurchCRM's setup wizard allows unauthenticated attackers to inject arbitrary PHP code during the initial installation process, leading to complete server compromise. The "$dbPassword" variable is not sanitized. This vulnerability exists due to an incomplete fix for CVE-2025-62521. This vulnerability is fixed in 7.1.0.
CVE-2026-28289CVSS 10FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. A patch bypass vulnerability for CVE-2026-27636 in FreeScout 1.8.206 and earlier allows any authenticated user with file upload permissions to achieve Remote Code Execution (RCE) on the server by uploading a malicious .htaccess file using a zero-width space character prefix to bypass the security check. The vulnerability exists in the sanitizeUploadedFileName() function in app/Http/Helper.php. The function contains a Time-of-Check to Time-of-Use (TOCTOU) flaw where the dot-prefix check occurs before sanitization removes invisible characters. This vulnerability is fixed in 1.8.207.
CVE-2025-46348CVSS 10YesWiki is a wiki system written in PHP. Prior to version 4.5.4, the request to commence a site backup can be performed and downloaded without authentication. The archives are created with a predictable filename, so a malicious user could create and download an archive without being authenticated. This could result in a malicious attacker making numerous requests to create archives and fill up the file system, or by downloading the archive which contains sensitive site information. This issue has been patched in version 4.5.4.
CVE-2024-5932CVSS 10The GiveWP – Donation Plugin and Fundraising Platform plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 3.14.1 via deserialization of untrusted input from the 'give_title' parameter. This makes it possible for unauthenticated attackers to inject a PHP Object. The additional presence of a POP chain allows attackers to execute code remotely, and to delete arbitrary files.
CVE-2025-47916CVSS 10Invision Community 5.0.0 before 5.0.7 allows remote code execution via crafted template strings to themeeditor.php. The issue lies within the themeeditor controller (file: /applications/core/modules/front/system/themeeditor.php), where a protected method named customCss can be invoked by unauthenticated users. This method passes the value of the content parameter to the Theme::makeProcessFunction() method; hence it is evaluated by the template engine. Accordingly, this can be exploited by unauthenticated attackers to inject and execute arbitrary PHP code by providing crafted template strings.

References

Track CVEs across your fleet automatically

Defensia scans your Linux servers and tells you exactly which ones are running vulnerable versions — including CVE-2024-47523. Free for 1 server.

Get started free