CVE-2026-109357 LibreNMS before 26.9.0 LDAP Filter Injection Authentication Bypass via Authorization Header
Unauthenticated attackers can gain admin access via LDAP filter injection in LibreNMS when using specific authorization modes without REMOTE_USER forwarding.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-109357?
CVE-2026-109357 is a critical authentication bypass vulnerability in librenms, published on 12 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-90
Which versions are affected by CVE-2026-109357?
How do I fix CVE-2026-109357?
No fix has been published for CVE-2026-109357 yet. Limit exposure of the affected software until one is available.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-109357 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-109357 exists.
Sources
Also known as GHSA-7cmx-65c5-8h8v, GHSA-rx4g-rhf6-xw5x.