CVE-2026-56624 Apache MINA SSHD vulnerability
Improper certificate validation in Apache MINA SSHD (server-side). Apache MINA SSHD is a Java library for client-side and server-side SSH. Server-side OpenSSH user certificate validation during user authentication in an Apache MINA SSHD server did not check for the unsupported force-command or verify-required options that could be embedded in the certificate, nor did it validate these options. As a result it was possible that a user could authenticate with such a certificate that included a force-command option but still was able to execute other commands. What other command exactly would be available to the user depends on the implementation of the server. This issue is fixed in Apache MINA SSHD 2.19.0 and 3.0.0-M5. Applications are advised to upgrade to these versions. The fix rejects OpenSSH user certificates that include these options, since Apache MINA SSHD implements neither force-command nor sk-*-cert-v01@openssh.com user certificates (which are the only ones for which verify-required would make sense).
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Apache Software Foundation Apache MINA SSHD should be reviewed and updated if it matches the affected versions. The recommended fix is to apply the vendor-supported patched version or the mitigation steps below, then retest the public website with Fixnx.
Who is affected
Affected versions
- <= 2.18.0
- <= 3.0.0-M4
Fixed versions
- Apply the latest vendor-supported patched version.
How to fix it
CVE-2026-56624 affects Apache MINA SSHD and involves security-control failure. Successful exploitation may affect the confidentiality, integrity, or availability of the affected workflow. Prioritize internet-facing, privileged, automation, and production deployments. Upgrade Apache MINA SSHD to 2.19.0, 3.0.0-M5, or a later fixed release for the deployed branch.
- Inventory every deployment, device, package, plugin, container, build, and environment that uses Apache MINA SSHD.
- Compare the installed version with the recorded affected range: <= 2.18.0, <= 3.0.0-M4.
- Upgrade Apache MINA SSHD to 2.19.0, 3.0.0-M5, or a later fixed release for the deployed branch.
- Until patched, reduce public exposure, disable the affected workflow where practical, and allow access only from trusted users and systems.
- Review configuration, roles, tokens, network paths, and exposed endpoints connected to Apache MINA SSHD; remove access that is not required.
- Review application, system, proxy, and audit logs for requests and behavior linked to the affected feature and CVE.
- If exploitation is suspected, isolate affected assets, preserve evidence, rotate exposed credentials or keys, restore trusted data, and rebuild compromised systems before returning them to service.
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Verify the fix
- Confirm every affected asset now runs the fixed vendor-supported release or has the documented mitigation for CVE-2026-56624 in place.
- Use a safe regression test to confirm the affected security-control failure path no longer produces the vulnerable behavior.
- Confirm temporary access controls, endpoint restrictions, network blocks, and least-privilege settings remain effective after the update.
- Review post-remediation logs and rerun Fixnx plus the relevant package, dependency, firmware, browser, or product-specific security check.
- Document affected assets, versions, changes, validation evidence, reviewed logs, and any credential rotation, cleanup, or replacement completed.
Related categories
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FAQ
What is affected by CVE-2026-56624?
Apache Software Foundation Apache MINA SSHD versions listed as affected should be reviewed: <= 2.18.0, <= 3.0.0-M4.
What should I fix first?
Start with internet-facing sites, admin panels, login flows, plugins, themes, modules, packages, and systems that process user-controlled input or sensitive data.
How do I confirm the fix worked?
Apply the patched version or mitigation, clear caches where relevant, retest the affected workflow, and run a new Fixnx scan to verify public website exposure signals.
How are Fixnx security risk categories chosen?
Fixnx keeps one canonical risk page and assigns only broad, relevant categories such as ecosystem, technology area, or vulnerability class.