How severe is CVE-2026-109357?

CVE-2026-109357 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-109357 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (39th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-109357?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2026-109357 published?

CVE-2026-109357 was published on 2026-10-12 and last updated on 2026-10-15.

CVE-2026-109357

CVE-2026-109357 is a high-severity vulnerability with a CVSS 3.x base score of 8.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-90.

Key facts

Severity: High (CVSS 3.x base score 8.1)
CVSS v4: 9.2
EPSS exploit prediction: 0% (39th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-90
Published: 2026-10-12
Last modified: 2026-10-15

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.

Frequently asked questions

What is CVE-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 can send a wildcard username via HTTP Basic Authorization (PHP_AUTH_USER) to match all users and groups and gain admin access.
How severe is CVE-2026-109357?: CVE-2026-109357 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-109357 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (39th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-109357?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2026-109357 published?: CVE-2026-109357 was published on 2026-10-12 and last updated on 2026-10-15.

References

Other CWE-90 (LDAP Injection) vulnerabilities

CVE-2026-44930 — Critical (CVSS 9.8): An LDAP injection vulnerability in the LDAP Certificate repository of the XKMS server in Apache CXF may allow an…
CVE-2026-25560 — Critical (CVSS 9.8): WeKan versions prior to 8.19 contain an LDAP filter injection vulnerability in LDAP authentication. User-supplied…
CVE-2024-54852 — Critical (CVSS 9.8): When LDAP connection is activated in Teedy versions between 1.9 to 1.12, the username field of the login form is…
CVE-2024-33868 — Critical (CVSS 9.8): An issue was discovered in linqi before 1.4.0.1 on Windows. There is LDAP injection.
CVE-2011-4069 — Critical (CVSS 9.8): html/admin/login.php in PacketFence before 3.0.2 allows remote attackers to conduct LDAP injection attacks and…
CVE-2017-14596 — Critical (CVSS 9.8): In Joomla! before 3.8.0, inadequate escaping in the LDAP authentication plugin can result in a disclosure of a username…

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