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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.

PUBLISHED Reserved 2026-03-30 | Published 2026-04-09 | Updated 2026-04-09 | Assigner GitHub_M




HIGH: 8.2CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N

Problem types

CWE-90: Improper Neutralization of Special Elements used in an LDAP Query ('LDAP Injection')

Product status

< 26.1.6
affected

References

github.com/...e/core/security/advisories/GHSA-jpm7-f59c-mp54 exploit

github.com/...e/core/security/advisories/GHSA-jpm7-f59c-mp54

github.com/...ommit/016f66cb4620cd48183fa97843f343bb71813c6e

cve.org (CVE-2026-34578)

nvd.nist.gov (CVE-2026-34578)

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