Improper certificate validation in Apache MINA SSHD (server-side). (CVE-2026-56624)
Description
Apache MINA SSHD server-side improperly validated OpenSSH user certificates during authentication by not checking for unsupported force-command or verify-required options. This allowed users with certificates containing a force-command option to authenticate but still execute other commands, depending on server implementation. The issue is fixed in Apache MINA SSHD versions 2.19.0 and 3.0.0-M5 by rejecting such certificates.
CVSS v3.1
Score 7.3high
Affected software
pkg:deb/ubuntu/mina?arch=source&distro=xenialpkg:deb/ubuntu/mina2?arch=source&distro=xenialpkg:deb/ubuntu/mina?arch=source&distro=bionicpkg:deb/ubuntu/mina2?arch=source&distro=bionicpkg:deb/ubuntu/mina?arch=source&distro=focalpkg:deb/ubuntu/mina2?arch=source&distro=focalpkg:deb/ubuntu/mina?arch=source&distro=jammypkg:deb/ubuntu/mina2?arch=source&distro=esm-apps/jammypkg:deb/ubuntu/mina?arch=source&distro=noblepkg:deb/ubuntu/mina2?arch=source&distro=esm-apps/noblepkg:deb/ubuntu/mina2?arch=source&distro=stonkingpkg:deb/ubuntu/mina2?arch=source&distro=esm-apps/resoluteRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in Apache MINA SSHD server-side involves improper validation of OpenSSH user certificates during user authentication. Specifically, the server did not check for unsupported force-command or verify-required options embedded in the certificate, nor validate these options. This flaw could allow a user to authenticate with a certificate containing a force-command option but still execute commands other than the forced one, depending on the server implementation. The fix, introduced in versions 2.19.0 and 3.0.0-M5, rejects OpenSSH user certificates that include these unsupported options, as Apache MINA SSHD does not implement force-command or sk-*[email protected] user certificates.
Potential Impact
Successful exploitation allows a user with a certificate containing a force-command option to authenticate but potentially execute commands beyond the intended forced command. The exact commands available depend on the server's implementation. This could lead to unauthorized command execution with the privileges of the authenticated user. The CVSS score is 7.3 (High impact on confidentiality and integrity, no impact on availability).
Mitigation Recommendations
A fix is available in Apache MINA SSHD versions 2.19.0 and 3.0.0-M5. Applications using affected versions should upgrade to these fixed versions to reject OpenSSH user certificates containing unsupported force-command or verify-required options. No other mitigations are indicated by the vendor advisory.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- UBUNTU-CVE-2026-56624
- Osv Schema Version
- 1.7.0
- Ecosystems
- ["Ubuntu:16.04:LTS","Ubuntu:18.04:LTS","Ubuntu:20.04:LTS","Ubuntu:22.04:LTS","Ubuntu:Pro:22.04:LTS","Ubuntu:24.04:LTS","Ubuntu:Pro:24.04:LTS","Ubuntu:26.10","Ubuntu:Pro:26.04:LTS"]
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6ad3f5e92cdf04f6566634e4
Added to database: 10/17/2026, 22:25:45 UTC
Last enriched: 10/18/2026, 00:36:14 UTC
Last updated: 10/18/2026, 00:36:14 UTC
Views: 3
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