External risk intelligence

Apache MINA SSHD LDAP Injection Authentication Bypass

CVE advisorySeverity: CRITICAL (CVSS 9.1)

CVE-2026-94053

The vulnerability resides in a library used to build SSH servers. SSH is a standard protocol for remote access, and implementations using this library to provide authentication services are commonly deployed as network-accessible, internet-facing remote management gateways or access points.

Authentication Bypass

Halo Surface Signal: 4 out of 5 — likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A vulnerability has been identified in the Apache MINA SSHD library's optional LDAP authentication component that could allow unauthorized access. This issue impacts SSH servers that utilize this specific component for password or public key authentication against an LDAP server. The primary concern is to confirm if your environment uses this component and is therefore exposed.

Authentication bypass in SSH LDAP component.
Affects remote access if LDAP auth is used.
Confirm relevance and assess exposure.

Attack Path

How an attacker could exploit the issue

An attacker could bypass authentication on SSH servers that use the optional LDAP integration. By sending specially crafted credentials to the vulnerable component, an attacker could trick the system into granting unauthorized access, potentially leading to compromised confidentiality and integrity of the system.

Requires network access.
Triggers via specially crafted LDAP queries.
Allows unauthorized access to the system.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability could allow an unauthenticated attacker to bypass SSH authentication when the optional `sshd-ldap` component is used and configured for password or public key authentication. This could expose sensitive system data and user credentials.

SSH authentication credentials.
Unauthenticated LDAP injection.
Unauthorized access to systems.

Operational Fix

Recommended remediation, mitigation, and detection steps

The SSHD-LDAP component of Apache MINA SSHD is vulnerable to authentication bypass via LDAP injection. This affects SSH servers that use this optional component for password or public key authentication against an LDAP server. Responsibility likely falls to application owners and platform teams managing the SSH services, with initial triage involving identifying affected systems, assessing their exposure and criticality, and confirming ownership before planning remediation.

Own the issue: Application and Platform Owners.
Verify first: Identify and confirm affected SSH servers.
Action: Plan remediation based on risk and vendor coordination.

Supplementary metadata

CVSS vector

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Frequently asked questions

What is Apache MINA SSHD and the sshd-ldap component?

Apache MINA SSHD is a Java library developers use to build SSH clients and servers. It handles the low-level mechanics of secure remote communication. The sshd-ldap component is an optional feature for this library that allows an SSH server to offload user authentication to an existing LDAP directory. By using this, servers can verify passwords or public keys against a centralized identity store rather than local system files.

What does CWE-90 mean for CVE-2026-94053?

CWE-90 refers to improper neutralization of special elements used in an LDAP query, commonly known as LDAP injection. In the context of CVE-2026-94053, the sshd-ldap component fails to properly escape characters in the authentication filter. Because the inputs are not sanitized, an attacker can manipulate the query logic to trick the LDAP server into confirming a successful login even when the credentials provided are not valid.

How can an attacker trigger this authentication bypass?

The vulnerability is triggered by providing specific input that includes LDAP metacharacters, such as the asterisk wildcard, during the SSH login process. If a server is configured to use the vulnerable component, the system incorrectly processes these characters. Note that servers not using the sshd-ldap component, or those that use MINA SSHD solely for client-side operations, are not affected by this specific flaw.

Is my system at risk according to Halo Surface Signal?

Halo Surface Signal identifies this as a 'Likely' risk because Apache MINA SSHD is frequently utilized to build internet-facing remote management gateways. If your infrastructure uses this library to host SSH services that are accessible over the network, the risk is higher. Systems that are restricted to internal networks or do not expose SSH services to untrusted segments may have a smaller attack surface, but should still be evaluated.

How do I address this CVE-2026-94053 vulnerability?

The first step is to perform an inventory of your applications to determine if they use the Apache MINA SSHD library and, specifically, if the sshd-ldap component is enabled for authentication. Once identified, the recommended path is to update your application dependencies to version 2.20.0 or 3.0.0-M6. These versions implement proper filtering as defined in RFC 4515, which neutralizes the ability to inject malicious LDAP syntax.

References

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.