IRONSMITHINTEL
CRITICALCVSS9.8
|
Actively Exploited
|CISA KEV|CVE-2021-35394|Auth: none — unauthenticated|Reboot: required|Manual only

Realtek Jungle SDK Remote Code Execution Vulnerability

RealTek Jungle SDK contains multiple memory corruption vulnerabilities which can allow an attacker to perform remote code execution.

Published Aug 16, 2021 · Updated May 16, 2026
Why patchRisk explained in plain English
Worst-case scenarioIf unpatched

A remote attacker, without authentication, can achieve full data confidentiality loss, arbitrary modification of data, complete denial of service or system unavailability. Federal agencies are required to remediate by 2021-12-24 under CISA BOD 22-01.

How the attack worksNo clicks needed

This is a OS Command Injection (CWE-78) vulnerability in Realtek Jungle Software Development Kit (SDK). Realtek Jungle SDK version v2.x up to v3.4.14B provides a diagnostic tool called 'MP Daemon' that is usually compiled as 'UDPServer' binary. The binary is affected by multiple memory corruption vulnerabilities and an arbitrary command injection vulnerability that can be exploited by remote unauthenticated attackers. Exploitation requires remote network access, low attack complexity, no authentication required, and no user interaction required.

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Phishing link

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Malicious file

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Server compromised

Am I affected?Quick check

Probably yes if any of these apply:

IT Security
Running rtl819x jungle software development kit: 2.0 ≤ v ≤ 3.4.14b
Real-world incidentsWhat we've seen

Active exploitation documented in the wild. Threat-research write-up: https://www.iot-inspector.com/blog/advisory-multiple-issues-realtek-sdk-iot-supply-chain

How to patch

Manual remediation steps

Apply the Vendor Patch

This vulnerability is in the CISA Known Exploited Vulnerabilities catalog — apply the vendor's security update as soon as possible.

CISA required action: Apply updates per vendor instructions.

References

    1
    Vendor advisory: https://www.realtek.com/en/cu-1-en/cu-1-taiwan-en
    1
    NVD entry: https://nvd.nist.gov/vuln/detail/CVE-2021-35394
    1
    CISA KEV: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-35394
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