High severity · published Oct 12, 2026
CVE-2026-109357
LibreNMS before 26.9.0 LDAP Filter Injection Authentication Bypass via Authorization Header
8.1
CVSS
0.6%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.6% · higher than 48% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
LI
librenms · librenms
before 26.9.0 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-109357
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-109357
vendor-advisory
https://github.com/librenms/librenms/security/advisories/GHSA-7cmx-65c5-8h8v
third-party-advisory
https://www.vulncheck.com/advisories/librenms-before-26.9.0-ldap-filter-injection-authentication-bypass-via-authorization-header
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