# CVE-2026-11522: Tenda W20E stack overflow in formSetPortMirror

Source: https://junglewise.ai/threats/cve-2026-11522-tenda-w20e-stack-overflow-in-formsetportmirror  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-08. Updated: 2026-06-08  
License: CC BY 4.0 with a link back

CVE-2026-11522 · Severity: high · CVSS 8.8 · Published 2026-06-08

A security vulnerability has been identified in the Tenda W20E enterprise router, a device used to manage business network traffic. An attacker can exploit this flaw to cause the router to crash or potentially take full control of the device. This could lead to significant network downtime, unauthorized access to internal communications, or a foothold for further attacks on the corporate network.

Technologies: [Tenda W20E](https://junglewise.ai/threats/technologies/w20e). Vendors: [Tenda](https://junglewise.ai/threats/vendors/tenda).

## Quick answers

**Is CVE-2026-11522 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-11522 being exploited in the wild.

**How severe is CVE-2026-11522?** High severity, with a CVSS score of 8.8, published 8 June 2026.

**Which products and versions are affected?** Tenda W20E 15.11.0.6.

**Is there a fix for CVE-2026-11522?** 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-2026-11522 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-11522?** Check whether you run Tenda W20E 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 Tenda W20E router (firmware version 15.11.0.6) within the 'formSetPortMirror' function of the '/goform/setPortMirror' endpoint. The vulnerability is caused by the unsafe use of 'sprintf' when processing the user-supplied 'portMirrorMirroredPorts' parameter, which is copied into a fixed-size 256-byte stack buffer without adequate bounds checking. An authenticated attacker can provide a specially crafted string longer than 256 bytes to overwrite the saved Link Register (LR) on the stack. This can result in a service crash (DoS) or remote code execution (RCE). A public exploit (PoC) is available.

## Affected products

- Tenda W20E 15.11.0.6

## Timeline

- 2026-06-08: disclosed: Vulnerability published and CVE assigned

## References

- [https://github.com/Robots10/IoT_vlu/blob/main/reports/Tenda/formSetPortMirror/portMirrorMirroredPorts.md](https://github.com/Robots10/IoT_vlu/blob/main/reports/Tenda/formSetPortMirror/portMirrorMirroredPorts.md)
- [https://vuldb.com/cve/CVE-2026-11522](https://vuldb.com/cve/CVE-2026-11522)
- [https://vuldb.com/submit/836469](https://vuldb.com/submit/836469)
- [https://vuldb.com/vuln/369142](https://vuldb.com/vuln/369142)
- [https://vuldb.com/vuln/369142/cti](https://vuldb.com/vuln/369142/cti)
- [https://www.tenda.com.cn/](https://www.tenda.com.cn/)

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