WDR201A WiFi Extender Stack-Based Buffer Overflow via firewall.cgi

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Summary

CVECVE-2026-41927
StatePUBLISHED
AssignerVulnCheck
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-05-04 20:16:19 UTC
Updated2026-05-05 19:47:31 UTC
DescriptionWDR201A 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.

Risk And Classification

Primary CVSS: v4.0 8.3 HIGH from [email protected]

CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS: 0.000420000 probability, percentile 0.125500000 (date 2026-05-05)

Problem Types: CWE-121 | CWE-121 CWE-121: Stack-based Buffer Overflow

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary8.3HIGHCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N/E:X/C...
4.0CNACVSS8.3HIGHCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
High
Attack Requirements
None
Privileges Required
None
User Interaction
None
Confidentiality
Low
Integrity
Low
Availability
High
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Shenzhen Yipu Commercial And Trading Co. Ltd WDR201A WiFi Extender affected 1.02 semver Not specified

References

ReferenceSourceLinkTags
mstreet97.github.io/security-research/iot/vulnerability-disclosure/ai-assisted-re... [email protected] mstreet97.github.io
www.made-in-china.com/showroom/yeapook [email protected] www.made-in-china.com
www.vulncheck.com/advisories/wdr201a-wifi-extender-stack-based-buffer-overflow-... [email protected] www.vulncheck.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Daniele Berardinelli (en)

CNA: Matteo Strada (en)

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