CVE-2021-35394

Name: CVE-2021-35394
Creator: NVD / NIST
Published: 2021-08-16T12:15:07.267+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10Actively ExploitedEPSS 99.86%

Last modified Jun 17, 2026

CVE-2021-35394 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. 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.. CISA has confirmed active exploitation in the wild. EPSS estimates a 99.86% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1

9.8/10

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

EPSS Probability

99.86%

100.0th percentile

Probability of exploitation in the next 30 days. Learn more

Exploitation Status

This vulnerability is listed in CISA’s Known Exploited Vulnerabilities catalog, confirming active exploitation in the wild. Federal agencies must remediate by Dec 24, 2021.

Weakness Enumeration

CWE-78

Affected Software

Vendor	Product	Versions
Realtek	Rtl819x Jungle Software Development Kit	>= 2.0, <= 3.4.14b

References

https://www.iot-inspector.com/blog/advisory-multiple-issues-realtek-sdk-iot-supply-chainBroken Link, Exploit, Third Party Advisory
https://www.realtek.com/en/cu-1-en/cu-1-taiwan-enBroken Link, Patch, Vendor Advisory
https://www.realtek.com/images/safe-report/Realtek_APRouter_SDK_Advisory-CVE-2021-35392_35395.pdfPatch, Vendor Advisory
https://www.securityfocus.com/archive/1/534765Broken Link, Third Party Advisory, VDB Entry
https://www.iot-inspector.com/blog/advisory-multiple-issues-realtek-sdk-iot-supply-chainBroken Link, Exploit, Third Party Advisory
https://www.realtek.com/en/cu-1-en/cu-1-taiwan-enBroken Link, Patch, Vendor Advisory
https://www.realtek.com/images/safe-report/Realtek_APRouter_SDK_Advisory-CVE-2021-35392_35395.pdfPatch, Vendor Advisory
https://www.securityfocus.com/archive/1/534765Broken Link, Third Party Advisory, VDB Entry
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-35394US Government Resource

Timeline

Published: Aug 16, 2021
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2021-35394?

How severe is CVE-2021-35394?

CVE-2021-35394 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 99.86% probability of exploitation in the next 30 days. This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog.

How do I fix CVE-2021-35394?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-35394?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST