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Tcis 3 FirmwareOperating system · Zenitel

CVE-2025-59818

CRITICAL · 9.8 CVSS v3.1 Published 2026-02-04
Fix available
A fix is available. Upgrade to 9.2.3.3 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
This vulnerability allows authenticated attackers to execute arbitrary commands on the underlying system using the file name of an uploaded file.

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

A command injection vulnerability exists in the file upload functionality where the file name of an uploaded file is not properly sanitized before being processed, allowing authenticated attackers to inject arbitrary OS commands through specially crafted file names that get executed on the underlying system.

MitigationImplement strict input validation and sanitization of file names during upload processing, disable shell interpretation of filenames, and apply the principle of least privilege to the file upload functionality.

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
Tcis 3 FirmwareOperating system
Affected:< 9.2.3.3

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
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 TCIS web management interface and navigate to System > Status or use the CLI command 'tcisctl version' or check via API endpoint /api/system/info
    Affected if The firmware version displayed is below 9.2.3.3 (e.g., 9.2.2.x, 9.1.x, etc.)
  2. Verify file upload functionality is enabled
    Navigate to System > File Management or Settings > Upload in the TCIS admin interface, or check for presence of /upload endpoint in the API
    Affected if File upload functionality is present and accessible to authenticated users
  3. Confirm authentication is enabled for the web interface
    Check that the TCIS web interface requires login credentials by attempting to access the admin pages or reviewing authentication settings in Security > Users
    Affected if The system accepts authentication credentials, which is required for exploitation since the attacker needs to be authenticated
  4. Review file name handling configuration
    Examine system logs or configuration files related to file upload processing - look for settings controlling filename sanitization in /etc/tcis/upload.conf or similar
    Affected if No explicit filename sanitization or shell escape configuration is found in the upload handling settings

You are affected if your TCIS firmware version is below 9.2.3.3 and authenticated users can access the file upload functionality without additional security controls on filename processing.

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 9.2.3.3 or later
Fixed in 9.2.3.3
Interim mitigation

Implement strict input validation and sanitization of file names during upload processing, disable shell interpretation of filenames, and apply the principle of least privilege to the file upload functionality.

Recommended fix Moderate confidence

Tcis 3 Firmware version 9.2.3.3 or later

  1. 1. Identify the current Tcis 3 Firmware version by accessing the device administration interface or checking system information.
  2. 2. Navigate to the official Zenitel support portal or firmware download section at www.zenitel.com.
  3. 3. Locate and download the Tcis 3 Firmware version 9.2.3.3 or later.
  4. 4. Create a backup of the current device configuration before proceeding with the firmware update.
  5. 5. During a planned maintenance window, upload the new firmware file through the device's web-based administration interface or appropriate update mechanism.
  6. 6. Verify the firmware upgrade was successful by confirming the new version number in the system information.
  7. 7. Test that normal station functionality operates correctly after the upgrade.
  8. 8. Validate that file upload functionality works as expected with the patched version.
Caveat Review Zenitel release notes for any changes to configuration formats or functionality that may require adjustment after upgrading

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

Fix this in Tcis 3 Firmware Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing6.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,980
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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-2025-59818 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