---
id: CVE-2026-109357
title: >-
  LibreNMS before 26.9.0 contains an LDAP filter injection in ldap-authorization
  and ad-authorization modes because usernames are inserted unescaped into LDAP
  search filters and authentication only checks user existence
summary: >-
  LibreNMS before 26.9.0 contains an LDAP filter injection in ldap-authorization
  and ad-authorization modes because usernames are inserted unescaped into LDAP
  search filters and authentication only checks user existence. When REMOTE_USER
  i…
severity: high
cvss: 8.1
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-90
published: '2026-10-12'
updated: '2026-10-12'
sourceUpdated: '2026-10-12T17:17:33.020'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-109357'
references:
  - url: >-
      https://github.com/librenms/librenms/security/advisories/GHSA-7cmx-65c5-8h8v
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/librenms-before-26.9.0-ldap-filter-injection-authentication-bypass-via-authorization-header
    label: disclosure@vulncheck.com
tags:
  - nvd
ingestedAt: '2026-10-12T18:00:08.213Z'
---

## Overview

LibreNMS before 26.9.0 contains an LDAP filter injection in ldap-authorization and ad-authorization modes because usernames are inserted unescaped into LDAP search filters and authentication only checks user existence. When REMOTE_USER is not forwarded, unauthenticated attackers can send a wildcard username via HTTP Basic Authorization (PHP_AUTH_USER) to match all users and groups and gain admin access.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.