Vulnerability Monitor

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CVE-2021-35393

Realtek Jungle SDK version v2.x up to v3.4.14B provides a 'WiFi Simple Config' server that implements both UPnP and SSDP protocols. The binary is usually named wscd or mini_upnpd and is the successor to miniigd. The server is vulnerable to a stack buffer overflow vulnerability that is present due to unsafe parsing of the UPnP SUBSCRIBE/UNSUBSCRIBE Callback header. Successful exploitation of this vulnerability allows remote unauthenticated attackers to gain arbitrary code execution on the affected device.

Security Impact Summary

This vulnerability carries a CRITICAL severity rating with a CVSS v3.1 score of 9.8, indicating it can be exploited remotely over the network with relatively low complexity without requiring user interaction and does not require pre-existing privileges . The vulnerability impacts confidentiality (data exposure), integrity (unauthorized modifications), and availability (service disruption) for affected systems. Impacting 1 product from realtek organizations running these solutions should prioritize assessment and patching.

Historical Context

Reported in 2021, this vulnerability emerged during an era marked by increased sophistication in supply chain attacks, cloud infrastructure vulnerabilities, and software-as-a-service (SaaS) security challenges. Security practices during this period emphasized zero-trust architectures, container security, and API protection.

Published

2021-08-16T12:15:07.230

Last Modified

2025-08-13T15:22:43.290

Status

Analyzed

Source

[email protected]

Severity

CVSSv3.1: 9.8 (CRITICAL)

CVSSv2 Vector

AV:N/AC:L/Au:N/C:C/I:C/A:C

Access Vector: NETWORK
Access Complexity: LOW
Authentication: NONE
Confidentiality Impact: COMPLETE
Integrity Impact: COMPLETE
Availability Impact: COMPLETE

Exploitability Score

10.0

Impact Score

10.0

Weaknesses

Type: Primary
CWE-787

Affected Vendors & Products

Type	Vendor	Product	Version/Range	Vulnerable?
Application	realtek	rtl819x_jungle_software_development_kit	≤ 3.4.14b	Yes

References

https://www.iot-inspector.com/blog/advisory-multiple-issues-realtek-sdk-iot-supply-chain Broken Link, Exploit, Third Party Advisory ([email protected])
https://www.realtek.com/en/cu-1-en/cu-1-taiwan-en Broken Link, Patch, Vendor Advisory ([email protected])
https://www.realtek.com/images/safe-report/Realtek_APRouter_SDK_Advisory-CVE-2021-35392_35395.pdf Patch, Vendor Advisory ([email protected])
https://www.iot-inspector.com/blog/advisory-multiple-issues-realtek-sdk-iot-supply-chain Broken Link, Exploit, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://www.realtek.com/en/cu-1-en/cu-1-taiwan-en Broken Link, Patch, Vendor Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://www.realtek.com/images/safe-report/Realtek_APRouter_SDK_Advisory-CVE-2021-35392_35395.pdf Patch, Vendor Advisory (af854a3a-2127-422b-91ae-364da2661108)

How SecUtils Interprets This CVE

SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For realtek's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.