dbcve.org
OpensshApplication · OpenBSD

CVE-2026-35414

HIGH · 8.1 CVSS v3.1 Published 2026-04-02
Fix available
A fix is available. Upgrade to 10.3 or later.
See remediation →
90/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
OpenSSH before 10.3 mishandles the authorized_keys principals option in uncommon scenarios involving a principals list in conjunction with a Certificate Authority that makes certain use of comma characters.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

OpenSSH before version 10.3 contains a parsing vulnerability in the authorized_keys 'principals' option when used alongside a Certificate Authority. The vulnerability stems from improper handling of comma characters within principals lists in specific CA authentication scenarios, potentially allowing authentication bypass or incorrect principal assignment.

MitigationUpgrade OpenSSH server installations to version 10.3 or later to resolve the parsing issue. Review existing authorized_keys configurations involving principals options and Certificate Authority setups for potential edge cases.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
OpensshApplication
Affected:< 10.3

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify OpenSSH version
    Run 'sshd -V' or 'ssh -V' to determine the installed OpenSSH version number
    Affected if Version is earlier than 10.3 (for example, 10.2, 10.1, 10.0, or any version number below 10.3)
  2. Locate authorized_keys files with principals option
    Search for authorized_keys files containing the 'principals' keyword, typically in user .ssh directories or in /etc/ssh/ for system-wide keys, using grep -r 'principals' ~/.ssh/authorized_keys /etc/ssh/authorized_keys/ 2>/dev/null
    Affected if Any authorized_keys entry contains a 'principals' option setting a list of allowed principal names
  3. Verify Certificate Authority authentication is in use
    Check if sshd_config contains 'TrustedUserCAKeys' or 'AuthorizedPrincipalsFile' directives, or look for certificate files (files ending in -cert.pub) in /etc/ssh/ or user .ssh directories
    Affected if The system uses CA-signed user certificates for authentication via TrustedUserCAKeys or similar CA-based configuration
  4. Examine CA certificate principals configuration
    Review the CA key policy and any existing issued certificates to identify whether comma characters appear within principal names in the certificates, which may require examining the certificate contents using 'ssh-keygen -L -f <certificate-file>'
    Affected if CA-signed certificates embed comma characters within the principal names listed in the certificate

The environment is affected if OpenSSH version is below 10.3 AND the authorized_keys configuration uses the principals option with CA-signed certificates that contain comma characters in their principal names.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 10.3 or later
Fixed in 10.3
Interim mitigation

Upgrade OpenSSH server installations to version 10.3 or later to resolve the parsing issue. Review existing authorized_keys configurations involving principals options and Certificate Authority setups for potential edge cases.

Recommended fix Moderate confidence

OpenSSH 10.3

  1. Backup your current SSH configuration and keys before making any changes
  2. Verify your current OpenSSH version using: ssh -V or sshd -V
  3. Upgrade OpenSSH to version 10.3 or later using your system's package manager (e.g., apt-get update && apt-get install openssh-server for Debian/Ubuntu, or yum/dnf for RHEL/CentOS)
  4. After upgrade, verify the new version is installed: ssh -V
  5. Test SSH connections in a controlled manner before deploying to production
  6. Ensure any authorized_keys files with principals options and certificate authority configurations are still functioning correctly
Caveat Review OpenSSH 10.3 release notes for any configuration or compatibility changes; minor configuration adjustments may be needed for certificate-based authentication using principals

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Openssh Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-35414 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data