---
id: "CVE-2021-35394"
kind: "vulnerability"
aliases: ["CVE-2021-35394"]
title: "Realtek Jungle Software Development Kit (SDK): Realtek Jungle SDK Remote Code Execution Vulnerability"
severity: "critical"
cvss: 10.0
epss: 0.99877
exploited: true
status: "open"
category: "infrastructure"
products: [{"name": "Realtek Jungle Software Development Kit (SDK)", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["embedded-devices", "exploited", "infrastructure", "realtek", "routers", "self-hosted"]
not_affected_if: ["managed-hosting", "no-realtek-jungle-sdk"]
published_at: "2021-08-16T12:15:07+00:00"
first_seen_at: "2026-10-23T19:11:53+00:00"
updated_at: "2026-10-23T21:57:35+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-35394", "first_seen_at": "2026-10-23T19:11:53+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2021-35394", "first_seen_at": "2026-10-23T19:13:44+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-35394", "first_seen_at": "2026-10-23T21:57:35+00:00"}]
---

# Realtek Jungle Software Development Kit (SDK): Realtek Jungle SDK Remote Code Execution Vulnerability

Realtek Jungle SDK, firmware used in network devices such as routers and switches, contains memory corruption bugs that allow remote code execution. An attacker who reaches the device over the network can run code on it, which typically means full control of the device.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:Realtek Jungle Software Development Kit (SDK) affected ? fixed ?

## Fix

Apply updates per vendor instructions, as CISA directs; the sources do not name a fixed version.

## Timeline

- 2026-10-23T19:11:53+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-35394
- 2026-10-23T19:13:44+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2021-35394
- 2026-10-23T21:57:35+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2021-35394

## From the sources

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.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_