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CVE-2026-34578

OPNsense has an LDAP Injection via Unsanitized Username in Authentication

Published: Apr 9, 2026Updated: Apr 14, 2026 Sources: CVE List NVDCWE-90
NVD MITRE
8.2CVSSHIGH
EPSS Score
0.4%
Top 66.9%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

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.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:HI:LA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:LIntegrity
Low
A:NAvailability
None
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Weaknesses

CWE-90

Affected Products

opnsenseopnsense
On-prem
Networking Infrastructure / firewall
coreopnsense
On-prem
Networking Infrastructure / firewall
opnsenseoss-projectNetworking Infrastructure

Exploitability

Official Patch Available
Workaround Available

References

https://github.com/opnsense/core/commit/016f66cb4620cd48183fa97843f343bb71813c6e
github.com
https://github.com/opnsense/core/security/advisories/GHSA-jpm7-f59c-mp54
github.com

Timeline

Published
Apr 9, 2026
Last Updated
Apr 14, 2026

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