Tn 5900 FirmwareOperating system · Moxa

CVE-2023-33238

CRITICAL · 9.8 CVSS v3.1 Published 2023-08-17
Fix available
A fix is available. Upgrade to after 3.3 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click Patch available

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
TN-4900 Series firmware versions v1.2.4 and prior and TN-5900 Series firmware versions v3.3 and prior are vulnerable to the command injection vulnerability. This vulnerability stems from inadequate input validation in the certificate management function, which could potentially allow malicious users to execute remote code on affected devices.

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
How this class of weakness works · CWE-78

User input reaches a shell or system command without being fully separated from the command itself, so an attacker can append their own instructions. Because these run with the application's privileges, it often means full control of the host. The lasting fix is to avoid the shell entirely — call APIs directly and pass arguments as data, never as concatenated strings.

General guidance for the os command injection class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

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
Tn 5900 FirmwareOperating system
Affected:<= 3.3
Tn 4900 FirmwareOperating system
Affected:<= 1.2.4

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

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 a release after 3.3
Vendor patch www.moxa.com →
Recommended fix Moderate confidence

TN-5900: firmware > 3.3; TN-4900: firmware > 1.2.4 (obtain specific fixed version from Moxa vendor advisory)

  1. 1. Identify the exact model number (TN-5900 or TN-4900) of the affected Moxa device
  2. 2. Access the Moxa support website at www.moxa.com and navigate to the product support page for your model
  3. 3. Download the latest firmware version from the downloads section
  4. 4. Consult the product manual for firmware upgrade instructions
  5. 5. Backup the current device configuration before performing the upgrade
  6. 6. Upload and install the new firmware following the vendor's documented procedure
  7. 7. Verify the firmware version after upgrade to confirm the patch was applied
  8. 8. Restore the configuration if a backup was made
Caveat Review Moxa release notes for any configuration or feature changes between versions; some legacy functionality may require reconfiguration

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

We can identify the exact fixed release, upgrade, and verify it in staging — typical engagement from $3,550. Get the upgrade done

Scan for this in your stack

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Check whether your project pulls in CVE-2023-33238 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

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-2023-33238 in production — separate from our analysis above.

No notes yet

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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
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