CVE-2026-109357

LibreNMS before 26.9.0 LDAP Filter Injection Authentication Bypass via Authorization Header

State: Published
Severity: 9.2 Critical
Published: Oct 12, 2026
Updated: Oct 15, 2026
Reserved: Oct 12, 2026

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.

Scores

CVSS	Score	Vector	Source
4.0	9.2 Critical	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	VulnCheck
3.1	8.1 High	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H	VulnCheck

Weaknesses

CWE-90 Improper Neutralization of Special Elements used in an LDAP Query ('LDAP Injection')

Affected Products

Product	Versions
librenmslibrenms	before 26.9.0Affected 26.9.0Not affected

References

GitHub Security Advisory (GHSA-7cmx-65c5-8h8v)vendor-advisory
VulnCheck Advisory: LibreNMS before 26.9.0 LDAP Filter Injection Authentication Bypass via Authorization Headerthird-party-advisory

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