CVE-2026-5608
Received Received - Intake
Stack-Based Buffer Overflow in Belkin F9K1122 Remote Form Handler

Publication date: 2026-04-06

Last updated on: 2026-04-30

Assigner: VulDB

Description
A vulnerability was detected in Belkin F9K1122 1.00.33. Affected is the function formWlanSetup of the file /goform/formWlanSetup. The manipulation of the argument webpage results in stack-based buffer overflow. The attack may be performed from remote. The exploit is now public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.
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Meta Information
Published
2026-04-06
Last Modified
2026-04-30
Generated
2026-06-16
AI Q&A
2026-04-06
EPSS Evaluated
2026-06-15
NVD
CVE-2026-5608
EUVD
EUVD-2026-19146
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
belkin f9k1122_firmware 1.00.33
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-119 The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.
CWE-121 A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).
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Executive Summary

The vulnerability exists in the Belkin F9K1122 router firmware version 1.00.33, specifically in the formWlanSetup function of the web interface. It involves a stack-based buffer overflow caused by improper handling of the "webpage" parameter. This parameter is copied into a buffer without bounds checking, allowing an attacker to overflow the buffer by sending a specially crafted HTTP POST request to the /goform/formWlanSetup endpoint.

Exploiting this vulnerability can lead to denial of service (DoS) or remote code execution on the affected device.

Impact Analysis

This vulnerability can have serious impacts including causing the router to crash (denial of service) or allowing an attacker to execute arbitrary code remotely. This means an attacker could potentially take control of the affected device, disrupt network connectivity, or use the device as a foothold to attack other systems on the network.

Detection Guidance

This vulnerability can be detected by monitoring for suspicious HTTP POST requests sent to the /goform/formWlanSetup endpoint of the Belkin F9K1122 router. Specifically, look for POST requests containing an excessively long or malformed "webpage" parameter, which is used to trigger the stack-based buffer overflow.

A practical detection method is to capture network traffic and filter for POST requests targeting /goform/formWlanSetup with unusually large payloads or parameters.

  • Use a network packet capture tool like tcpdump or Wireshark to monitor HTTP POST requests to /goform/formWlanSetup.
  • Example tcpdump command to capture relevant traffic: tcpdump -i <interface> -A 'tcp port 80 and (((ip[2:2] - ((ip[0]&0xf)<<2)) - ((tcp[12]&0xf0)>>2)) != 0)' | grep '/goform/formWlanSetup'
  • Alternatively, use curl or similar tools to test the endpoint by sending a crafted POST request with a long "webpage" parameter to see if the device responds abnormally.
Mitigation Strategies

Immediate mitigation steps include restricting access to the vulnerable router's web interface to trusted networks only, such as internal LAN segments, to prevent remote exploitation.

Additionally, monitor and block suspicious HTTP POST requests targeting /goform/formWlanSetup, especially those with unusually long "webpage" parameters.

If possible, disable remote management features on the router to reduce exposure.

Since the vendor has not responded with a patch, consider replacing or upgrading the device firmware if a fixed version becomes available.

Compliance Impact

The provided information does not specify any direct impact of this vulnerability on compliance with common standards and regulations such as GDPR or HIPAA.

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