What’s Vulnerable › Vulnerabilities

CVE-2026-109357: LibreNMS before 26.9.0 LDAP Filter Injection Authentication Bypass via Authorization Header

• Severity: high (CVSS 8.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-12 · updated 2026-10-15
• Weakness: CWE-90

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.

Affected products

• librenms: before 26.9.0 — fixed in 26.9.0

How to fix

Upgrade to a fixed version: librenms 26.9.0. Check the vendor advisory for mitigations.

References

• https://github.com/librenms/librenms/security/advisories/GHSA-7cmx-65c5-8h8v
• https://www.vulncheck.com/advisories/librenms-before-26.9.0-ldap-filter-injection-authentication-bypass-via-authorization-header
• https://github.com/librenms/librenms/security/advisories/GHSA-7cmx-65c5-8h8v

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