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Vulnerabilities

Vulnerability · CVE-2026-109357

LibreNMS before 26.9.0 LDAP Filter Injection Authentication Bypass via Authorization Header

Published Oct 12, 2026 · catalog updated Oct 15, 2026 · LibreNMS before 26.9.0 LDAP

Check if you run it

No confirmed exploitation is on record for CVE-2026-109357. EPSS is 0.46%. Act only if a listed version of LibreNMS before 26.9.0 LDAP is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (LibreNMS before 26.9.0 LDAP).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Critical9.2
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.46%
Remediation
Advisory link
Affected products
vendor librenms librenms

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor librenms librenmsversion unspecified

How to fix CVE-2026-109357

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-109357. EPSS is 0.46%. Act only if a listed version of LibreNMS before 26.9.0 LDAP is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-90: LDAP Injection. EPSS 0.46%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 12, 2026 · NIST NVD

    Detected

    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 a

  2. Oct 15, 2026 · NIST NVD

    Updated

    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 a

Sources

  • CIRCL Vulnerability LookupVulnerability recordCVE-2026-109357

    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

    vulnerability.circl.lu
  • CVE.orgVulnerability recordCVE-2026-109357

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-109357

    30-day exploitation probability 0.5%

    first.org
  • NIST NVDVulnerability recordCVE-2026-109357

    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

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.