Is CVE-2026-34578 in the CISA KEV catalog?

No. CVE-2026-34578 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-34578?

CVE-2026-34578 has a CVSS v3 base score of 8.2 (HIGH).

What is the EPSS score for CVE-2026-34578?

CVE-2026-34578 has an EPSS score of 0.41% (34th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-34578?

Upgrade opnsense to 26.1.6 or later.

CVE & CISA-KEV Catalog

CVE-2026-34578

HIGH

8.2

CVSS v3

NVD

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.

CWE-90

How to fix

Remediation Available

opnsenseNVD

Affected:< 26.1.6Fixed in:26.1.6CVE-2026-34578derived from NVD

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityLow

AvailabilityNone

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

Exploit Intelligence

0.41%probability of exploitation in 30 days

34thpercentile

Low risk: more likely to be exploited than 34% of all known CVEs.

References

Patch1

github.com

Exploit1

github.com

Related Vulnerabilities

Other CWE-90 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2016-9299	Critical	9.8	97%	-	-
CVE-2017-14596	Critical	9.8	6.5%	-	-
CVE-2016-8750	Medium	6.5	5.3%	-	Fix
CVE-2021-43350	Critical	9.8	4.4%	-	Fix
CVE-2017-4927	High	7.5	2.3%	-	Fix
CVE-2024-27310	Medium	5.3	2.3%	-	Fix

Embed a live status badge for CVE-2026-34578

Markdown

[![CVE-2026-34578](https://tridentstack.com/cve/badge/CVE-2026-34578.svg)](https://tridentstack.com/cve/CVE-2026-34578)

HTML

<a href="https://tridentstack.com/cve/CVE-2026-34578"><img src="https://tridentstack.com/cve/badge/CVE-2026-34578.svg" alt="CVE-2026-34578"></a>

Find and fix vulnerabilities across your fleet

TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.

See how it works Start freeThis CVE lookup is free and always will be.

This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-14.