CVE-2026-109357

LibreNMS before 26.9.0 LDAP Filter Injection Authentication Bypass via Authorization Header

Published Oct 12, 2026 CVSS 4.0 · 9.2 Critical EPSS < 1% KEV · Not listed
Description
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

No solution or workaround provided in the CVE record

Tracking

Sign in to view the affected projects.

Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description 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.
Title LibreNMS before 26.9.0 LDAP Filter Injection Authentication Bypass via Authorization Header
First Time appeared Librenms
Librenms librenms
Weaknesses CWE-90
CPEs cpe:2.3:a:librenms:librenms:*:*:*:*:*:*:*:*
Vendors & Products Librenms
Librenms librenms
References
Metrics cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'}

cvssV4_0

{'score': 9.2, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
VulnCheck
Published
Updated
Oct 15, 2026, 2:53 AM
Reserved
Oct 12, 2026, 2:21 PM
Status
Awaiting Analysis
Published
Oct 12, 2026, 5:17 PM
Modified
Oct 15, 2026, 8:33 PM