# CVE-2026-86165: Tenda HG10 buffer overflow in formURL

Source: https://junglewise.ai/threats/cve-2026-86165-tenda-hg10-buffer-overflow-in-formurl  
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-2026-86165 · Severity: critical · CVSS 9.8 · Published 2026-09-06

The Tenda HG10 router's web administration interface contains a buffer overflow vulnerability in the formURL function. An attacker can send a specially crafted HTTP request to crash the router or potentially execute arbitrary code, rendering the device unavailable and requiring a manual restart. This affects remote network security since attackers can disable the firewall protecting an organization's internal network without authentication.

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

## Quick answers

**Is CVE-2026-86165 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-86165 being exploited in the wild.

**How severe is CVE-2026-86165?** Critical severity, with a CVSS score of 9.8, published 6 September 2026.

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

**Is there a fix for CVE-2026-86165?** 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-2026-86165 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-86165?** 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 classic stack-based buffer overflow exists in the Boa web server's formURL handler (/boaform/admin/formURL) due to unsafe use of strcpy() when processing the "Keywd" parameter. The vulnerable code retrieves the Keywd argument from HTTP POST requests and copies it into a fixed-size buffer without length validation. An attacker can send an oversized Keywd parameter via a remote HTTP POST request to overflow the buffer, overwriting adjacent stack memory. This results in immediate denial of service (crash) and potentially code execution, depending on memory layout and exploitation sophistication. No authentication is required; the attack is network-reachable. Patches are not yet publicly available.

## Affected products

- Tenda HG10 300001138

## Timeline

- 2026-09-06: disclosed
- 2026-09-06: other: Exploit published on GitHub

## References

- [https://github.com/SunnyYANGyaya/cuicuishark-sheep-fishIOT/blob/main/Tenda/HG10/bof-formURL-keywd.md](https://github.com/SunnyYANGyaya/cuicuishark-sheep-fishIOT/blob/main/Tenda/HG10/bof-formURL-keywd.md)
- [https://vuldb.com/cve/CVE-2026-86165](https://vuldb.com/cve/CVE-2026-86165)

## 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 formWanRedirect](https://junglewise.ai/threats/cve-2026-86166-tenda-hg10-buffer-overflow-in-formwanredirect)
- [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)