CVE-2021-35395

9.8 CRITICAL CISA KEV - Actively Exploited
Published: August 16, 2021 Modified: November 07, 2025

Description

Realtek Jungle SDK version v2.x up to v3.4.14B provides an HTTP web server exposing a management interface that can be used to configure the access point. Two versions of this management interface exists: one based on Go-Ahead named webs and another based on Boa named boa. Both of them are affected by these vulnerabilities. Specifically, these binaries are vulnerable to the following issues: - stack buffer overflow in formRebootCheck due to unsafe copy of submit-url parameter - stack buffer overflow in formWsc due to unsafe copy of submit-url parameter - stack buffer overflow in formWlanMultipleAP due to unsafe copy of submit-url parameter - stack buffer overflow in formWlSiteSurvey due to unsafe copy of ifname parameter - stack buffer overflow in formStaticDHCP due to unsafe copy of hostname parameter - stack buffer overflow in formWsc due to unsafe copy of 'peerPin' parameter - arbitrary command execution in formSysCmd via the sysCmd parameter - arbitrary command injection in formWsc via the 'peerPin' parameter Exploitability of identified issues will differ based on what the end vendor/manufacturer did with the Realtek SDK webserver. Some vendors use it as-is, others add their own authentication implementation, some kept all the features from the server, some remove some of them, some inserted their own set of features. However, given that Realtek SDK implementation is full of insecure calls and that developers tends to re-use those examples in their custom code, any binary based on Realtek SDK webserver will probably contains its own set of issues on top of the Realtek ones (if kept). Successful exploitation of these issues allows remote attackers to gain arbitrary code execution on the device.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://www.iot-inspector.com/blog/advisory-multiple-issues-realtek-sdk-iot-supply-chain
Source: cve@mitre.org
Broken Link Exploit Third Party Advisory
https://www.realtek.com/en/cu-1-en/cu-1-taiwan-en
Source: cve@mitre.org
Broken Link Patch Vendor Advisory
https://www.iot-inspector.com/blog/advisory-multiple-issues-realtek-sdk-iot-supply-chain
Source: af854a3a-2127-422b-91ae-364da2661108
Broken Link Exploit Third Party Advisory
https://www.realtek.com/en/cu-1-en/cu-1-taiwan-en
Source: af854a3a-2127-422b-91ae-364da2661108
Broken Link Patch Vendor Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-35395
Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
US Government Resource

7 reference(s) from NVD

Quick Stats

CVSS v3 Score
9.8 / 10.0
EPSS (Exploit Probability)
93.7%
100th percentile
Exploitation Status
Actively Exploited
Remediation due: 2021-11-17

Affected Vendors

realtek