# CVE-2026-5608: Belkin F9K1122 stack-based buffer overflow in formWlanSetup

Source: https://junglewise.ai/threats/cve-2026-5608-belkin-f9k1122-stack-based-buffer-overflow-in-formwlansetup  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-04-06. Updated: 2026-07-24  
License: CC BY 4.0 with a link back

CVE-2026-5608 · Severity: high · CVSS 8.8 · Published 2026-04-06

A security vulnerability has been identified in the Belkin F9K1122 wireless router. This flaw exists in the device's web-based setup interface, which is used to manage Wi-Fi settings. If exploited, a remote attacker could cause the router to crash or potentially take full control of the device, leading to a complete loss of internet connectivity and the potential compromise of network traffic.

Vendors: [Belkin](https://junglewise.ai/threats/vendors/belkin).

## Quick answers

**Is CVE-2026-5608 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-5608 being exploited in the wild.

**How severe is CVE-2026-5608?** High severity, with a CVSS score of 8.8, published 6 April 2026.

**Which products and versions are affected?** Belkin F9k1122 1.00.33.

**Is there a fix for CVE-2026-5608?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-5608 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-5608?** Check whether you run Belkin F9k1122 or Belkin F9k1122 Firmware at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A stack-based buffer overflow vulnerability exists in the Belkin F9K1122 router firmware version 1.00.33. The flaw is located within the 'formWlanSetup' function in the '/goform/formWlanSetup' file. The vulnerability is triggered when the 'webpage' argument is processed; specifically, the 'p_reboot_msg' variable is passed to a 'strcpy' function call without adequate length validation, overflowing the 'reboot_msg' buffer. An attacker with network access can exploit this by sending a specially crafted POST request. Successful exploitation can lead to a denial of service (DoS) or remote code execution (RCE). As of the advisory date, the vendor has not responded to disclosure attempts, and a public exploit is available.

## Affected products

- Belkin F9K1122 1.00.33

## Timeline

- 2026-04-05: disclosed: Vulnerability first reported to VulDB
- 2026-04-06: advisory: NVD publication date

## References

- [https://github.com/Litengzheng/vul_db/blob/main/Belkin/vul_80/README.md](https://github.com/Litengzheng/vul_db/blob/main/Belkin/vul_80/README.md)
- [https://vuldb.com/submit/785315](https://vuldb.com/submit/785315)
- [https://vuldb.com/vuln/355399](https://vuldb.com/vuln/355399)
- [https://vuldb.com/vuln/355399/cti](https://vuldb.com/vuln/355399/cti)