# CVE-2026-9429: Tenda F1202 stack overflow in formWrlExtraSet

Source: https://junglewise.ai/threats/cve-2026-9429-tenda-f1202-stack-overflow-in-formwrlextraset  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-25. Updated: 2026-05-26  
License: CC BY 4.0 with a link back

CVE-2026-9429 · Severity: high · CVSS 8.8 · Published 2026-05-25

A security vulnerability exists in the Tenda F1202 wireless router, a device used to provide internet connectivity in homes and small offices. An attacker can exploit this flaw to crash the router or potentially take full control of the device. This could lead to a complete loss of internet access or allow an unauthorized person to monitor network traffic and access sensitive data.

Technologies: [Tenda F1202](https://junglewise.ai/threats/technologies/f1202). Vendors: [Tenda](https://junglewise.ai/threats/vendors/tenda).

## Quick answers

**Is CVE-2026-9429 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-9429 being exploited in the wild.

**How severe is CVE-2026-9429?** High severity, with a CVSS score of 8.8, published 25 May 2026.

**Which products and versions are affected?** Tenda F1202 1.2.0.20(408).

**Is there a fix for CVE-2026-9429?** 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-2026-9429 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-9429?** Check whether you run Tenda F1202 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 'httpd' binary of the Tenda F1202 router, specifically within the 'formWrlExtraSet' function in '/goform/WrlExtraSet'. The vulnerability is caused by a lack of length validation on user-supplied parameters (identified as 'delno' or 'GO') before they are processed by functions like 'sprintf'. A remote attacker with low privileges can exploit this by sending a specially crafted POST request containing an overly long string. Successful exploitation can lead to a crash of the web service (Denial of Service) or potentially remote code execution (RCE). A public exploit (PoC) is available.

## Affected products

- Tenda F1202 1.2.0.20(408)

## Timeline

- 2026-05-25: disclosed: Vulnerability disclosed via VulDB and GitHub PoC
- 2026-05-25: advisory: CVE-2026-9429 published

## References

- [https://github.com/Litengzheng/vuldb_new2/blob/main/F1202/vul_31/README.md](https://github.com/Litengzheng/vuldb_new2/blob/main/F1202/vul_31/README.md)
- [https://vuldb.com/submit/813912](https://vuldb.com/submit/813912)
- [https://vuldb.com/vuln/365410](https://vuldb.com/vuln/365410)
- [https://vuldb.com/vuln/365410/cti](https://vuldb.com/vuln/365410/cti)
- [https://www.tenda.com.cn/](https://www.tenda.com.cn/)

## Related threats

- [Tenda F1202 stack overflow in fromPptpUserAdd](https://junglewise.ai/threats/cve-2026-9431-tenda-f1202-stack-overflow-in-frompptpuseradd)
- [Tenda F1202 stack overflow in formGstDhcpSetSer](https://junglewise.ai/threats/cve-2026-9430-tenda-f1202-stack-overflow-in-formgstdhcpsetser)
- [Tenda F1202 stack overflow in fromPPTPUserSetting](https://junglewise.ai/threats/cve-2026-9428-tenda-f1202-stack-overflow-in-frompptpusersetting)