Tn 5916 Wv T FirmwareOperating system · Moxa

CVE-2021-46082

HIGH · 7.5 CVSS v3.1 Published 2022-02-18
Fix available
A fix is available. Upgrade to after 3.1 or later.
See remediation →
84/100
Remediation priority · High
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
Moxa TN-5900 v3.1 series routers, MGate 5109 v2.2 series protocol gateways, and MGate 5101-PBM-MN v2.1 series protocol gateways were discovered to contain a memory leak which allows attackers to cause a Denial of Service (DoS) via crafted packets.

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-401

Allocated memory is never released on some path, so a long-running service or a repeatedly triggered request steadily consumes memory until performance degrades or the process crashes. Attackers exploit it by simply driving the leaking path. Remediation is pairing every allocation with a release and using ownership patterns or tooling to catch what leaks.

General guidance for the memory leak 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 5916 Wv T FirmwareOperating system
Affected:<= 3.1
Tn 5916 Wv Ct T FirmwareOperating system
Affected:<= 3.1
Mgate 5109 FirmwareOperating system
Affected:<= 2.2
Mgate 5109 T FirmwareOperating system
Affected:<= 2.2
Mgate 5101 Pbm Mn FirmwareOperating system
Affected:<= 2.1
Mgate 5101 Pbm Mn T FirmwareOperating system
Affected:<= 2.1

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
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 3.1
Vendor patch www.moxa.com →
Recommended fix Moderate confidence

Firmware versions greater than the affected threshold: TN-5900 series > 3.1, MGate 5109 series > 2.2, MGate 5101-PBM-MN series > 2.1 - obtain exact fixed versions from Moxa security advisory

  1. 1. Identify the specific model number and current firmware version of the Moxa device from the affected product list (TN-5916 Wv T, TN-5916 Wv Ct T, MGate 5109, MGate 5109 T, MGate 5101-PBM-MN, or MGate 5101-PBM-MN T)
  2. 2. Download the latest firmware version from the official Moxa support website at www.moxa.com
  3. 3. Review the firmware upgrade instructions in the product manual
  4. 4. Backup the current device configuration before performing the upgrade
  5. 5. Upload and apply the new firmware via the device web interface or management console
  6. 6. Verify the upgrade was successful and confirm the device is functioning normally
  7. 7. After upgrade, verify the memory leak vulnerability is resolved by testing with the original crafted packet scenario or consulting the Moxa security advisory
Caveat Review Moxa release notes for any configuration or functionality changes between versions before upgrading

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 $1,950. Get the upgrade done

Scan for this in your stack

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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-2021-46082 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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