CVE-2026-41927: Stack Overflow

Description

WDR201A WiFi Extender (HW V2.1, FW LFMZX28040922V1.02) contains a stack-based buffer overflow vulnerability in the firewall.cgi and makeRequest.cgi binaries that allows unauthenticated attackers to overwrite the saved return address by sending a POST request with a Content-Length header exceeding 512 bytes. Attackers can exploit insufficient length validation in the fgets() call to achieve arbitrary code execution through return-oriented programming or return-to-libc techniques.

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EPSS — Exploit Prediction

0.0006

Probability of exploitation

0.18%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-121 CWE-121

References

Other 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-stack-based-buffer-overflow-via-firewall-cgi

Frequently Asked Questions

What is CVE-2026-41927? +

WDR201A WiFi Extender (HW V2.1, FW LFMZX28040922V1.02) contains a stack-based buffer overflow vulnerability in the firewall.cgi and makeRequest.cgi binaries that allows unauthenticated attackers to overwrite the saved return address by sending a POST request with a Content-Length header exceeding 512 bytes. Attackers can exploit insufficient length validation in the fgets() call to achieve arbitrary code execution through return-oriented programming or return-to-libc techniques.

How do I check if I'm vulnerable to CVE-2026-41927? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2026-41927