# CVE-2026-86166: Tenda HG10 buffer overflow in formWanRedirect

Source: https://junglewise.ai/threats/cve-2026-86166-tenda-hg10-buffer-overflow-in-formwanredirect  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-06. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-86166 · Severity: high · CVSS 8.8 · Published 2026-09-06

Tenda HG10 is a wireless router used for home and small business networks. A buffer overflow vulnerability in the web-based administration interface allows a remote attacker to crash the device or potentially execute arbitrary code by sending a specially crafted HTTP request. This could render the network inaccessible and disrupt customer connectivity.

Technologies: [Tenda HG10](https://junglewise.ai/threats/technologies/hg10). Vendors: [Tenda](https://junglewise.ai/threats/vendors/tenda).

## Quick answers

**Is CVE-2026-86166 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-86166 being exploited in the wild.

**How severe is CVE-2026-86166?** High severity, with a CVSS score of 8.8, published 6 September 2026.

**Which products and versions are affected?** Tenda HG10 300001138.

**Is there a fix for CVE-2026-86166?** 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-2026-86166 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-86166?** Check whether you run Tenda HG10 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 exists in the Boa web server's formWanRedirect function, triggered by improper validation of the 'if' parameter. The vulnerable code uses strcpy() to copy user-controlled input from an HTTP POST request into a fixed-size buffer without length checking. An attacker can send an oversized value for the 'if' parameter in a POST request to /boaform/formWanRedirect to overwrite adjacent stack memory. The attack requires no authentication and is remotely exploitable over the network. Confirmed impact includes denial of service (device crash); code execution may be possible depending on memory layout. No patch information is currently available.

## Affected products

- Tenda HG10 300001138

## Timeline

- 2026-09-06: disclosed

## References

- [https://github.com/SunnyYANGyaya/cuicuishark-sheep-fishIOT/blob/main/Tenda/HG10/bof-formWanRedirect-if.md](https://github.com/SunnyYANGyaya/cuicuishark-sheep-fishIOT/blob/main/Tenda/HG10/bof-formWanRedirect-if.md)
- [https://vuldb.com/cve/CVE-2026-86166](https://vuldb.com/cve/CVE-2026-86166)

## Related threats

- [Tenda HG7/HG9/HG10 stack buffer overflow in formLoopBack](https://junglewise.ai/threats/cve-2026-104610-a-security-vulnerability-has-been-detected-in-tenda-hg7-hg9-and)
- [Tenda HG10 OS command injection in formgponConf](https://junglewise.ai/threats/cve-2026-86167-tenda-hg10-os-command-injection-in-formgponconf)
- [Tenda HG10 buffer overflow in formURL](https://junglewise.ai/threats/cve-2026-86165-tenda-hg10-buffer-overflow-in-formurl)
- [Tenda HG10 buffer overflow in formWlanSetup SSID parameter](https://junglewise.ai/threats/cve-2026-85110-tenda-hg10-buffer-overflow-in-formwlansetup-ssid-parameter)
- [Tenda HG10 buffer overflow in Boa Web Server login handler](https://junglewise.ai/threats/cve-2026-85109-tenda-hg10-buffer-overflow-in-boa-web-server-login-handler)