CVE-2026-34578

OPNsense has an LDAP Injection via Unsanitized Username in Authentication

Published Apr 9, 2026 CVSS 3.1 · 8.2 High EPSS < 1% KEV · Not listed
Description
OPNsense is a FreeBSD based firewall and routing platform. Prior to 26.1.6, OPNsense's LDAP authentication connector passes the login username directly into an LDAP search filter without calling ldap_escape(). An unauthenticated attacker can inject LDAP filter metacharacters into the username field of the WebGUI login page to enumerate valid LDAP usernames in the configured directory. When the LDAP server configuration includes an Extended Query to restrict login to members of a specific group, the same injection can be used to bypass that group membership restriction and authenticate as any LDAP user whose password is known, regardless of group membership. This vulnerability is fixed in 26.1.6.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Opnsense opnsense
CPEs cpe:2.3:a:opnsense:opnsense:*:*:*:*:*:*:*:*
Vendors & Products Opnsense opnsense
Type Values Removed Values Added
First Time appeared Opnsense
Opnsense core
Vendors & Products Opnsense
Opnsense core
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description OPNsense is a FreeBSD based firewall and routing platform. Prior to 26.1.6, OPNsense's LDAP authentication connector passes the login username directly into an LDAP search filter without calling ldap_escape(). An unauthenticated attacker can inject LDAP filter metacharacters into the username field of the WebGUI login page to enumerate valid LDAP usernames in the configured directory. When the LDAP server configuration includes an Extended Query to restrict login to members of a specific group, the same injection can be used to bypass that group membership restriction and authenticate as any LDAP user whose password is known, regardless of group membership. This vulnerability is fixed in 26.1.6.
Title OPNsense has an LDAP Injection via Unsanitized Username in Authentication
Weaknesses CWE-90
References
Metrics cvssV3_1

{'score': 8.2, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Apr 9, 2026, 5:45 PM
Reserved
Mar 30, 2026, 4:56 PM
Status
Analyzed
Published
Apr 9, 2026, 3:16 PM
Modified
Oct 26, 2026, 10:10 PM