opnsense core up to 26.1.5 ldap_escape Username ldap injection

CVSS Meta Temp Score
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CTI Interest Score
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7.6$0-$5k0.43

Summaryinfo

A vulnerability was found in opnsense core up to 26.1.5. It has been rated as critical. This affects the function ldap_escape. The manipulation of the argument Username leads to ldap injection. This vulnerability is listed as CVE-2026-34578. The attack may be initiated remotely. There is no available exploit. Upgrading the affected component is advised.

Detailsinfo

A vulnerability, which was classified as critical, has been found in opnsense core up to 26.1.5. This issue affects the function ldap_escape. The manipulation of the argument username with an unknown input leads to a ldap injection vulnerability. Using CWE to declare the problem leads to CWE-90. The product constructs all or part of an LDAP query using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended LDAP query when it is sent to a downstream component. Impacted is confidentiality, integrity, and availability. The summary by CVE 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.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-34578 since 03/30/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1505 for this issue.

Upgrading to version 26.1.6 eliminates this vulnerability. Applying the patch 016f66cb4620cd48183fa97843f343bb71813c6e is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.7
VulDB Meta Temp Score: 7.6

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 8.2
CNA Vector (GitHub_M): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Ldap injection
CWE: CWE-90 / CWE-74 / CWE-707
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: core 26.1.6
Patch: 016f66cb4620cd48183fa97843f343bb71813c6e

Timelineinfo

03/30/2026 CVE reserved
04/09/2026 +10 days Advisory disclosed
04/09/2026 +0 days VulDB entry created
04/09/2026 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: GHSA-jpm7-f59c-mp54
Status: Confirmed

CVE: CVE-2026-34578 (🔒)
GCVE (CVE): GCVE-0-2026-34578
GCVE (VulDB): GCVE-100-356573

Entryinfo

Created: 04/09/2026 17:30
Changes: 04/09/2026 17:30 (67)
Complete: 🔍
Cache ID: 216:D1C:103

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