# CVE-2026-5629: Belkin F9K1015 stack-based buffer overflow in formSetFirewall

Source: https://junglewise.ai/threats/cve-2026-5629-belkin-f9k1015-stack-based-buffer-overflow-in-formsetfirewall  
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-2026-5629 · Severity: high · CVSS 8.8 · Published 2026-04-06

A security vulnerability exists in the Belkin F9K1015 wireless router, a device used to provide internet connectivity and network security for homes and small offices. An attacker can exploit this flaw to crash the router or potentially take full control of the device by sending a specially crafted web request. This could lead to a complete loss of internet access or unauthorized access to the network traffic passing through the router.

Technologies: [Belkin F9k1015](https://junglewise.ai/threats/technologies/f9k1015), [Belkin F9k1015 Firmware](https://junglewise.ai/threats/technologies/f9k1015-firmware). Vendors: [Belkin](https://junglewise.ai/threats/vendors/belkin).

## Quick answers

**Is CVE-2026-5629 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-5629 being exploited in the wild.

**How severe is CVE-2026-5629?** High severity, with a CVSS score of 8.8, published 6 April 2026.

**Which products and versions are affected?** Belkin F9k1015 1.00.10.

**Is there a fix for CVE-2026-5629?** 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-2026-5629 attacked?** It is attacked over the network, in device firmware.

**Am I affected by CVE-2026-5629?** Check whether you run Belkin F9k1015 or Belkin F9k1015 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 'formSetFirewall' function within the '/goform/formSetFirewall' endpoint of Belkin F9K1015 firmware version 1.00.10. The root cause is an unsafe 'strcpy' operation where a user-provided parameter, 'webpage', is copied into a fixed-size stack buffer ('last_url') without length validation. An attacker with network access and low-level privileges can trigger this overflow by sending a POST request with an excessively long string in the 'webpage' argument. 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 (PoC) is available.

## Affected products

- Belkin F9K1015 1.00.10

## Timeline

- 2026-04-06: disclosed: Vulnerability disclosed and public exploit released.
- 2026-04-06: advisory: NVD published the CVE entry.

## References

- [https://github.com/Litengzheng/vuldb_new/blob/main/Belkin%20F9K1015/vul_13/README.md](https://github.com/Litengzheng/vuldb_new/blob/main/Belkin%20F9K1015/vul_13/README.md)
- [https://vuldb.com/submit/785556](https://vuldb.com/submit/785556)
- [https://vuldb.com/vuln/355417](https://vuldb.com/vuln/355417)
- [https://vuldb.com/vuln/355417/cti](https://vuldb.com/vuln/355417/cti)

## Related threats

- [Belkin F9K1015 stack overflow in formSetSystemSettings](https://junglewise.ai/threats/cve-2026-5628-belkin-f9k1015-stack-overflow-in-formsetsystemsettings)
- [Belkin F9K1015 stack buffer overflow in formSetPassword](https://junglewise.ai/threats/cve-2026-5614-belkin-f9k1015-stack-buffer-overflow-in-formsetpassword)
- [Belkin F9K1015 stack-based buffer overflow in formReboot](https://junglewise.ai/threats/cve-2026-5613-belkin-f9k1015-stack-based-buffer-overflow-in-formreboot)
- [Belkin F9K1015 stack buffer overflow in formWlEncrypt](https://junglewise.ai/threats/cve-2026-5612-belkin-f9k1015-stack-buffer-overflow-in-formwlencrypt)
- [Belkin F9K1015 stack-based buffer overflow in formCrossBandSwitch](https://junglewise.ai/threats/cve-2026-5611-belkin-f9k1015-stack-based-buffer-overflow-in-formcrossbandswitch)