CVE-2021-35395
Confirmed PUBLISHEDRealtek 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...
Recommended Action
Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
At a Glance
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.
- CVE Published
- Aug 16, 2021
- Exploitation Reported
- Nov 03, 2021
- CVSS
- 9.8 Critical
- EPSS
- 98.0%
CVE References
- realtek.com/en/cu-1-en/cu-1-taiwan-en realtek.com · CVE Record https://www.realtek.com/en/cu-1-en/cu-1-taiwan-en
- realtek.com/images/safe-report/Realtek_APRouter_SDK_Advi... realtek.com · CVE Record https://www.realtek.com/images/safe-report/Realtek_APRouter_SDK_Advis...
- iot-inspector.com/blog/advisory-multiple-issues-realtek-sdk-io... iot-inspector.com · CVE Record https://www.iot-inspector.com/blog/advisory-multiple-issues-realtek-s...
Known Exploited Vulnerability Sources
Catalogues that list this CVE as a known exploited vulnerability.
Per-source evidence links for KEV attestations are available through the KEVIntel Pro API.
Learn about Pro API access| Source | Added |
|---|---|
| CISA First | 2021-11-03 00:00 UTC |
| The Shadowserver | 2026-05-31 00:00 UTC |
Scanner Artifacts
Scanner and exploit-framework references linked to this CVE.
| Scanner | Reference | Detected |
|---|---|---|
| Nuclei | https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2021/CVE-2021-35395.yaml | Apr 25, 2025 |
Virtual Patch
Compensating WAF rules to help reduce exposure to this CVE. Rule content and deployable vendor exports are available with KEVIntel Enterprise.
KEVIntel does not currently have a virtual patch for this CVE. When available, KEVIntel virtual patches ship as deployable ModSecurity, Cloudflare, and AWS WAF rules.
Enterprise feature. Virtual patch rule content and deployable vendor exports (ModSecurity, Cloudflare, AWS WAF) are available to KEVIntel Enterprise users.
CVSS Scores
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
AV:N/AC:L/Au:N/C:C/I:C/A:C
Exploitation Status
Exploited in the wild
Recorded 2021-11-03 00:00:00 UTC · CISA
Proof of concept available
Recorded 2026-06-12 14:20:23 UTC · Nuclei Templates
Scanner Integrations
Nuclei, Metasploit, and other scanner references for this CVE are listed on the Detection tab.
Potential Proof of Concepts
These PoCs are unverified and could contain malware. Use at your own risk.
nuclei · Created Unknown
Timeline
Key exploitation, disclosure, scanner coverage, and KEV attestation events for this CVE.
-
14:20 UTC about 2 months ago14:20 UTC · about 2 months ago
Public PoC available
Public proof-of-concept code published
-
00:00 UTC 2 months ago00:00 UTC · 2 months ago
KEV confirmed by The Shadowserver
Exploitation attested by an external source
-
00:00 UTC over 1 year ago00:00 UTC · over 1 year ago
Nuclei template available
Scanner coverage available
-
00:00 UTC over 4 years ago00:00 UTC · over 4 years ago
Added to CISA KEV
Listed in the CISA Known Exploited Vulnerabilities catalog
-
11:07 UTC almost 5 years ago11:07 UTC · almost 5 years ago
CVE published
Vulnerability disclosed publicly
-
00:00 UTC about 5 years ago00:00 UTC · about 5 years ago
CVE ID reserved
Identifier reserved by the CNA
Automate This Intelligence with the Pro API
Confidence scoring, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.
Pro API Example
GET /api/v2/pro/kevs/CVE-2021-35395
{
"cve_id": "CVE-2021-35395",
"title": "Realtek Jungle SDK version v2.x up to v3.4.14B provides an HTTP web server ex...",
"affected_vendor": "Realtek",
"affected_product": "Jungle SDK",
"affected_versions": [
{ "vendor": "...", "product": "...", "status": "affected", "display_label": "..." }
],
"confidence": "Confirmed",
"cvss_score": 9.8,
"epss_score": 0.97961,
"exploit_status": {
"exploited_in_the_wild": true,
"active_exploitation_observed": false
},
"sensor_telemetry": { "...": "Pro API fields" },
"proof_of_concepts": [ "..." ],
"scanner_integrations": [ "..." ]
}