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CVE-2021-35394

9.8, critical Known exploited

Realtek Jungle SDK Remote Code Execution Vulnerability

NVD (opens in a new tab) CVE.org (opens in a new tab) CISA KEV catalogue (opens in a new tab)
CVSS
9.8, critical critical CVSS v3.1
EPSS, next 30 days
100% higher than 99.9% of scored CVEs
Exploitation
Confirmed in the wild
Published
16 Aug 20215 years ago

Known exploited

CISA added this to the Known Exploited Vulnerabilities Catalog on 10 Dec 2021. US federal agencies had to remediate by 24 Dec 2021, a deadline that has passed.

Required action. Apply updates per vendor instructions.

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.

Details

Vendor
Realtek
Product
Rtl819x Jungle Software Development Kit
Weakness
CWE-78 (opens in a new tab)
Status
Analyzed
Updated
17 Jun 2026
Assigner
cve@mitre.org

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

References 5

Exploit code 1

Patches and fixes 2

Advisories 1

Other references 1

The kind is read from NVD's tags where present and from the shape of the URL otherwise, so treat it as a hint.

Other Realtek CVEs

Every Realtek CVE we hold

Same vendor in what we hold, not a known link between the flaws.

  • CVE-2021-35395 Realtek AP-Router SDK Buffer Overflow Vulnerability KEV EPSS 98% 9.8, critical
  • CVE-2014-8361 Realtek SDK Improper Input Validation Vulnerability KEV EPSS 100% 9.8, critical

Beyond this page

Is CVE-2021-35394 in your network?

This page tells you how dangerous CVE-2021-35394 is out there. Whether it sits on one of your devices, only a scan of your own network can tell. That is what our systems do, every day, for the companies we protect.

CVE-2021-35394 is in the CISA catalogue of exploited vulnerabilities: attackers are already exploiting it.

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    Ocelot scans your network on a schedule and reports every vulnerability it finds by its CVE identifier, with its CVSS score and how many of your hosts are affected. A finding like CVE-2021-35394 comes with the devices to patch.

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  • EXYS7950 KONDRA

    Detect it if it's exploited

    Until the patch is applied, Kondra monitors your network, events and endpoints in real time. It keeps an inventory of the software installed on every endpoint, and its anomaly detection rules flag what an attacker does once inside.

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Check your exposure

Assembled from the NVD 2.0 API, the CISA Known Exploited Vulnerabilities Catalog and FIRST EPSS. Scores are as of our last collection on 17 Oct 2026, not the live upstream state.