Which versions of Tew 657Brm are affected by CVE-2026-5349?

CVE-2026-5349 affects legacy Trendnet TEW-657BRM routers (discontinued 2011) and enables authenticated attackers to execute arbitrary code through a stack buffer overflow.

Is there a public PoC exploit available for CVE-2026-5349?

Yes, a public proof-of-concept exploit is available for CVE-2026-5349. Prioritise patching immediately. EPSS: 0.0%.

How to fix or mitigate CVE-2026-5349?

Within 24 hours: Inventory all Trendnet TEW-657BRM routers in production and document network segments where deployed. Within 7 days: Isolate affected devices to a segregated VLAN with restrictive access controls and disable remote administrative access. Within 30 days: Replace all TEW-657BRM units with currently supported router models from Trendnet or alternate vendors, or decommission devices if no longer operationally necessary.

Tew 657Brm CVE-2026-5349

Q: What is the CVSS score of CVE-2026-5349?

CVE-2026-5349 has a CVSS 4.0 base score of 7.4 (High). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. EPSS exploitation probability: 0.0%.

EUVD-2026-18358 HIGH

Stack-based Buffer Overflow (CWE-121)

2026-04-02 VulDB

Buffer Overflow Stack Overflow Tew 657Brm

7.4

CVSS 4.0 · NVD

Severity by source

NVD PRIMARY

7.4 HIGH

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Lifecycle Timeline

PoC Detected

Apr 07, 2026 - 14:15 vuln.today

Public exploit code

EUVD ID Assigned

Apr 02, 2026 - 16:00 euvd

EUVD-2026-18358

Analysis Generated

Apr 02, 2026 - 16:00 vuln.today

CVE Published

Apr 02, 2026 - 15:15 nvd

HIGH 7.4

DescriptionCVE.org

A vulnerability was identified in Trendnet TEW-657BRM 1.00.1. The affected element is the function add_apcdb of the file /setup.cgi. The manipulation of the argument mac_pc_dba leads to stack-based buffer overflow. The attack can be initiated remotely. The exploit is publicly available and might 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.

AnalysisAI

Stack-based buffer overflow in Trendnet TEW-657BRM router firmware 1.00.1 allows authenticated remote attackers to achieve arbitrary code execution via the mac_pc_dba parameter in /setup.cgi's add_apcdb function. The product was discontinued in 2011 and receives no vendor support. A public exploit exists on GitHub, significantly lowering the barrier for exploitation against unpatched devices still deployed in production environments.

Technical ContextAI

This vulnerability affects the Trendnet TEW-657BRM wireless router (CPE: cpe:2.3:a:trendnet:tew-657brm:*:*:*:*:*:*:*:*), specifically firmware version 1.00.1. The flaw is a CWE-121 stack-based buffer overflow in the add_apcdb function within the /setup.cgi CGI script handler. When processing the mac_pc_dba parameter, insufficient input validation allows an attacker to write beyond the allocated stack buffer boundary. Stack-based overflows are particularly dangerous in embedded device firmware because they can overwrite return addresses and enable arbitrary code execution with the privilege level of the web server process, typically root on embedded Linux systems. The CVSS vector indicates network-accessible attack surface (AV:N), low complexity (AC:L), and requires low privileges (PR:L), meaning any authenticated user can trigger the overflow. The vulnerability class is well-understood and reliably exploitable on devices without modern memory protection mechanisms like ASLR or stack canaries, which are often absent in legacy router firmware.

RemediationAI

No vendor-released patch exists or will be developed, as Trendnet discontinued the TEW-657BRM router in 2011 and explicitly states they no longer provide support or vulnerability confirmation for this product line. The only secure remediation is immediate hardware replacement with a currently supported router model that receives active security updates. Organizations that identify TEW-657BRM devices in their networks should prioritize decommissioning and replacement as part of standard end-of-life hardware retirement procedures. As an interim risk reduction measure until replacement, restrict administrative access to the device by implementing network segmentation, disabling remote management interfaces, enforcing strong authentication credentials if default passwords are in use, and limiting access to trusted administrator IP addresses via firewall rules. However, these workarounds do not eliminate the vulnerability and should be considered temporary measures only. The vendor advisory is available at https://vuldb.com/vuln/354702 with technical details and exploit code documented at https://github.com/panda666-888/vuls/blob/main/trendnet/tew-657brm/add_apcdb.md.