# CVE-2026-36808: Tenda W15E buffer overflow in formAddWebAuthUser

Source: https://junglewise.ai/threats/cve-2026-36808-tenda-w15e-buffer-overflow-in-formaddwebauthuser  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-09. Updated: 2026-06-09  
License: CC BY 4.0 with a link back

CVE-2026-36808 · Severity: info · Published 2026-06-09

The Tenda W15E enterprise router is vulnerable to a flaw that can be triggered by sending a specially crafted web request. This vulnerability affects the device's web management interface, specifically the user authentication configuration. An attacker can exploit this to crash the router, leading to a denial of service that disrupts internet connectivity and network operations for all connected users.

Technologies: [Tenda W15E](https://junglewise.ai/threats/technologies/w15e). Vendors: [Tenda](https://junglewise.ai/threats/vendors/tenda).

## Quick answers

**Is CVE-2026-36808 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-36808 being exploited in the wild.

**How severe is CVE-2026-36808?** Informational severity, published 9 June 2026.

**Which products and versions are affected?** Tenda W15E v15.11.0.10.

**Is there a fix for CVE-2026-36808?** 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-2026-36808 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-36808?** Check whether you run Tenda W15E 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 'formAddWebAuthUser' function of the Tenda W15E router (v15.11.0.10). The vulnerability is located in the handling of the 'webAuthUserInfo' HTTP parameter, which is retrieved via 'websGetVar'. The application uses 'strncpy' to copy data into a local buffer ('temp') based on the position of a newline character ('\n') found via 'strchr'. Because the length calculation '(int)pcVar1 - (int)p' does not account for the destination buffer's size, an attacker can provide a long string containing a newline character to overflow the buffer. This can be triggered via a network-reachable HTTP request to the 'addWebAuthUser' action, resulting in a process crash or device instability (Denial of Service).

## Affected products

- Tenda W15E v15.11.0.10

## Timeline

- 2026-03-18: other: CVE request submitted to MITRE
- 2026-06-06: disclosed: Public disclosure
- 2026-06-09: advisory: NVD published date

## References

- [https://github.com/xhh0124/SemVulLLM/tree/main/W15E/formAddWebAuthUser](https://github.com/xhh0124/SemVulLLM/tree/main/W15E/formAddWebAuthUser)

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