CVE-2021-35393Network attack vector

Unauthenticated code execution via UPnP Callback parsing

Published Aug 16, 2021 · Updated Aug 4, 2024

Stack buffer overflow in Realtek Jungle SDK 2.x through 3.4.14B allows remote attackers to execute arbitrary code without authentication. The wscd or mini_upnpd WiFi Simple Config server unsafely parses the Callback header in UPnP SUBSCRIBE and UNSUBSCRIBE requests into a stack buffer. Any network-reachable affected router exposes code-execution and service-crash consequences without credentials or user interaction.

CVSS severity9.8
Critical
EPSS probability70.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack buffer overflow in Realtek Jungle SDK 2.x through 3.4.14B allows remote attackers to execute arbitrary code without authentication. The wscd or mini_upnpd WiFi Simple Config server unsafely parses the Callback header in UPnP SUBSCRIBE and UNSUBSCRIBE requests into a stack buffer. Any network-reachable affected router exposes code-execution and service-crash consequences without credentials or user interaction.

The record

CVE
CVE-2021-35393
Published
Aug 16, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 16, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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