Tew 657brm FirmwareOperating system · Trendnet

CVE-2026-5354

HIGH · 8.8 CVSS v3.1 Published 2026-04-02
No fix yet
No fix has been published. The vendor has not shipped a fixed release or patch. You remain exposed.
See remediation →
94/100
Remediation priority · Urgent
Public exploit Remotely reachable 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
A flaw has been found in Trendnet TEW-657BRM 1.00.1. Affected by this vulnerability is the function vpn_connect of the file /setup.cgi. Executing a manipulation of the argument policy_name can lead to os command injection. The attack can be executed remotely. The exploit has been published and may be used. The vendor confirms, that "[t]he product in question (...) has been discontinued and end of life since June 23, 2011, that is more than 14 years ago. We no longer provide support for this product, so we are not able to confirm the vulnerabilities. We will make an announcement on our website's product support page and notify customers who registered their products with us." This vulnerability only affects products that are no longer supported by the maintainer.

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-77

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

General guidance for the 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
Tew 657brm FirmwareOperating system
Affected:= 1.00.1

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

CVSS:3.1/AV:N/AC:L/PR:L/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
Recommended fix High confidence
  1. Isolate the affected device on a restricted network segment away from untrusted users
  2. Configure firewall rules to block external access to TCP/UDP ports serving the /setup.cgi interface (typically HTTP port 80/HTTPS port 443)
  3. If the VPN functionality is not actively used, disable it at the network boundary or access the device locally only
  4. Monitor network traffic for any suspicious requests to the /setup.cgi endpoint containing unusual characters that may indicate exploitation attempts
  5. Consider replacing the end-of-life Trendnet TEW-657BRM device with a currently supported router that receives security updates
  6. If the device must remain in service, implement an upstream Web Application Firewall (WAF) to filter malicious requests targeting the policy_name parameter
Caveat There is no upgrade path available; Trendnet explicitly confirmed this product has been discontinued since June 2011 with no security support or patches provided

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

No vendor fix exists Tew 657brm Firmware has not published a patch for this.

There is no version to upgrade to and no patch to apply. Every affected install stays exposed until the vendor ships a fix — or somebody else builds one.

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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-2026-5354 in production — separate from our analysis above.

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