CVE-2026-34578

8.2 HIGH 0.4% exploit odds Fix listed Injection Network gear

What it is

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.

At a glance

Exploitability: Can be exploited over the network without logging in. High risk of data exposure.
Exploit odds: 0.4% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-04-09 15:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-10-26 22:10 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.4% in the next 30 days (EPSS).
Severity: 8.2 HIGH (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-04-09 15:16 UTC
Last modified: 2026-10-26 22:10 UTC
Exploit probability: 0.4% · EPSS, next 30 days
Weakness: CWE-90
Record status: Analyzed

Affected

Opnsense < 26.1.6

Attack profile CVSS 3.1 · 8.2

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: Low
Availability: None

Raw vector

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

Is it in your code?

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Fix and advisories

References

NVD record · CVE.org record