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CVE Record

CVE-2021-35392: Realtek Jungle SDK version v2.x up to v3.4.14B provides a 'WiFi Simple Config' server that implements both...

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 heap buffer overflow that is present due to unsafe crafting of SSDP NOTIFY messages from received M-SEARCH messages ST header.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This flaw affects Realtek Jungle SDK code used inside some routers and IoT devices. A malformed network discovery message can trigger a heap buffer overflow in the WiFi Simple Config service. The business risk comes from supply-chain exposure: organizations may own affected devices without knowing Realtek SDK code is inside them.

Executive priority

Make this a targeted asset-management and firmware-validation priority, especially for edge and IoT devices. Urgency is higher for internet-facing or untrusted-network exposure, but the source bundle lacks severity scoring, named affected models, and confirmed exploitation.

Technical view

CVE-2021-35392 is a heap buffer overflow in the Realtek Jungle SDK v2.x through v3.4.14B WiFi Simple Config server, commonly named wscd or mini_upnpd. The issue occurs when SSDP NOTIFY messages are unsafely crafted from received M-SEARCH ST headers. UPnP and SSDP exposure are the key technical indicators.

Likely exposure

Most likely exposure is embedded routers, access points, and IoT equipment built by OEMs using the affected Realtek SDK. The CVE bundle does not identify specific downstream device models, so exposure requires vendor, firmware, or SBOM confirmation.

Exploitation context

The provided sources do not state active exploitation, and the CVE is not marked CISA KEV. The flaw is remotely reachable where the affected UPnP/SSDP WiFi Simple Config service is exposed, but exploitability details and real-world targeting are not established in the bundle.

Researcher notes

The strongest evidence is the CVE description and Realtek/IoT Inspector references. Missing data includes CVSS, CWE mapping, downstream affected products, exploit status, and exact fixed versions. Avoid broad product claims without firmware-level confirmation.

Mitigation direction

  • Check Realtek and device-vendor advisories for fixed SDK or firmware guidance.
  • Update affected device firmware when the vendor confirms CVE-2021-35392 remediation.
  • Prioritize devices exposing UPnP, SSDP, wscd, or mini_upnpd on untrusted networks.
  • Remove or replace unsupported devices if no vendor fix is available.
  • Do not assume a device is unaffected solely because it is not Realtek-branded.

Validation and detection

  • Inventory routers, access points, and IoT devices for Realtek SDK usage.
  • Check firmware documentation, SBOMs, or vendor advisories for Jungle SDK versions v2.x through v3.4.14B.
  • Identify devices running WiFi Simple Config, UPnP, SSDP, wscd, or mini_upnpd services.
  • Confirm remediation status against Realtek or OEM firmware release notes.
  • Document unknown firmware lineage as unresolved supply-chain exposure.
Prepared
Confidence
medium
Sources
5

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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CVE-2021-35392 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
4Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.