CVE-2021-27239
8.8 · HIGHOverview
CVE-2021-27239 is a high-severity vulnerability affecting netgear d6220_firmware. It was published on March 29, 2021 and has a CVSS 3.1 base score of 8.8 (HIGH).
This vulnerability has a CVSS 3.1 base score of 8.8, rated HIGH. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.
Technical Description
This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of NETGEAR R6400 and R6700 firmware version 1.0.4.98 routers. Authentication is not required to exploit this vulnerability. The specific flaw exists within the upnpd service, which listens on UDP port 1900 by default. A crafted MX header field in an SSDP message can trigger an overflow of a fixed-length stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of root. Was ZDI-CAN-11851.
Remediation
Check the references section for vendor advisories and patches from netgear. Update d6220_firmware to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| netgear | d6220_firmware | >= 0, < 1.0.0.68 | Affected |
| netgear | d6400_firmware | >= 0, < 1.0.0.102 | Affected |
| netgear | d7000_firmware | >= 0, < 1.0.0.66 | Affected |
| netgear | d8500_firmware | >= 0, < 1.0.3.60 | Affected |
| netgear | dc112a_firmware | >= 0, < 1.0.0.54 | Affected |
| netgear | ex7000_firmware | >= 0, < 1.0.1.94 | Affected |
| netgear | ex7500_firmware | >= 0, < 1.0.0.72 | Affected |
| netgear | r6250_firmware | >= 0, < 1.0.4.48 | Affected |
| netgear | r6300_firmware | >= 0, < 1.0.4.50 | Affected |
| netgear | r6400_firmware | >= 0, < 1.0.1.68 | Affected |
References
Frequently Asked Questions
What is CVE-2021-27239?
CVE-2021-27239 is a high-severity vulnerability affecting netgear d6220_firmware. It was published on March 29, 2021 and has a CVSS 3.1 base score of 8.8 (HIGH).
How severe is CVE-2021-27239?
This vulnerability has a CVSS 3.1 base score of 8.8, rated HIGH. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2021-27239?
Check the references section for vendor advisories and patches from netgear. Update d6220_firmware to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2021-27239?
CyberStrike's AI-powered security agents can automatically detect CVE-2021-27239 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
Automated penetration testing that runs continuously, not just quarterly.
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Browser-based exploitation validates findings with real proof-of-concept.
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