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Infinera Mtc 9 FirmwareOperating system · Nokia

CVE-2025-27020

CRITICAL · 9.8 CVSS v3.1 Published 2025-12-08
Fix available
A fix is available. Upgrade to 23.0 or later.
See remediation →
100/100
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
Improper configuration of the SSH service in Infinera MTC-9 allows an unauthenticated attacker to execute arbitrary commands and access data on file system . This issue affects MTC-9: from R22.1.1.0275 before R23.0.

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

Improper SSH service configuration in Infinera MTC-9 allows unauthenticated remote attackers to execute arbitrary commands and access the file system. The vulnerability stems from the SSH service being accessible without valid authentication, likely due to a default configuration, exposed shell, or missing access controls.

MitigationUpdate MTC-9 firmware to R23.0 or later to remediate the improper SSH configuration. If immediate patching is not feasible, disable or restrict SSH access via network segmentation and firewall rules.

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
Infinera Mtc 9 FirmwareOperating system
Affected:>= 22.1.1.0275, < 23.0

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
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/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 the installed firmware version
    Access the MTC-9 device admin interface or use CLI command 'show version' or check system info page to retrieve the current firmware version
    Affected if The firmware version is 22.1.1.0275 or higher but lower than 23.0
  2. Verify SSH service is enabled
    Check if the SSH daemon is running on the device via CLI command 'show services' or via the web management interface under services/network settings
    Affected if SSH service is listed as running or enabled on the device
  3. Test SSH access without credentials
    Attempt to connect to the device SSH port (default 22) using an invalid username or no username at all, for example: 'ssh invaliduser@deviceIP' or 'ssh @deviceIP'
    Affected if SSH connection succeeds or presents a shell prompt without requiring any valid credentials
  4. Inspect SSH daemon configuration
    If SSH access is available, examine /etc/ssh/sshd_config or similar configuration file for 'PermitEmptyPasswords', 'PasswordAuthentication', or 'PermitRootLogin' settings
    Affected if SSH is configured to allow authentication with empty passwords, no valid users required, or root access without authentication

The device is affected if the firmware version falls within 22.1.1.0275 through 22.x.x.x (prior to 23.0) AND the SSH service permits unauthenticated access or allows shell access without valid credentials.

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 23.0 or later
Fixed in 23.0
Interim mitigation

Update MTC-9 firmware to R23.0 or later to remediate the improper SSH configuration. If immediate patching is not feasible, disable or restrict SSH access via network segmentation and firewall rules.

Recommended fix High confidence

R23.0 or later

  1. 1. Access the Infinera MTC-9 device management interface or console.
  2. 2. Verify current firmware version is >= 22.1.1.0275 and < 23.0 by checking the system information or running 'show version' command.
  3. 3. Obtain the R23.0 firmware upgrade package from Infinera's official support portal or trusted distribution channel.
  4. 4. Create a backup of the current configuration following Infinera backup procedures.
  5. 5. Upload the R23.0 firmware to the MTC-9 device using the device's firmware upgrade function (typically via web UI or CLI with 'software upload' or 'firmware upgrade' command).
  6. 6. Initiate the firmware upgrade process and wait for completion (do not power off the device during upgrade).
  7. 7. After reboot, verify the new firmware version is R23.0 or later using 'show version'.
  8. 8. Verify SSH service now requires authentication by attempting an unauthenticated connection (should be denied).
Caveat Major version upgrade from R22.x to R23.0 may introduce compatibility changes; review Infinera R23.0 release notes for any configuration or feature changes before upgrading

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

Fix this in Infinera Mtc 9 Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
15.0 hours of engineering $2,690
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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-2025-27020 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
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  • Version or environment caveats, and links to real fixes
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  • No spam, self-promotion, credentials, or personal data