CVE-2026-34578: OPNsense is a FreeBSD based firewall and routing platform. Prior to 26.1.6, OPNsense's LDAP authentication connector…
CVE-2026-34578 · Severity: high · CVSS 8.2 · Published 2026-04-09
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.
No. Junglewise Threat Intelligence has no report of CVE-2026-34578 being exploited in the wild.
How severe is CVE-2026-34578?
High severity, with a CVSS score of 8.2, published 9 April 2026.
Which products and versions are affected?
OPNsense. The advisory does not name versions.
Is there a fix for CVE-2026-34578?
No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
Am I affected by CVE-2026-34578?
Check whether you run OPNsense. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.