CVE-2020-3421
8.6 · HIGHOverview
CVE-2020-3421 is a high-severity vulnerability affecting cisco ios_xe. It was published on September 24, 2020 and has a CVSS 3.1 base score of 8.6 (HIGH).
This vulnerability has a CVSS 3.1 base score of 8.6, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
Multiple vulnerabilities in the Zone-Based Firewall feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause the device to reload or stop forwarding traffic through the firewall. The vulnerabilities are due to incomplete handling of Layer 4 packets through the device. An attacker could exploit these vulnerabilities by sending a certain sequence of traffic patterns through the device. A successful exploit could allow the attacker to cause the device to reload or stop forwarding traffic through the firewall, resulting in a denial of service. For more information about these vulnerabilities, see the Details section of this advisory.
Remediation
Check the references section for vendor advisories and patches from cisco. Update ios_xe 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 |
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Frequently Asked Questions
What is CVE-2020-3421?
CVE-2020-3421 is a high-severity vulnerability affecting cisco ios_xe. It was published on September 24, 2020 and has a CVSS 3.1 base score of 8.6 (HIGH).
How severe is CVE-2020-3421?
This vulnerability has a CVSS 3.1 base score of 8.6, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2020-3421?
Check the references section for vendor advisories and patches from cisco. Update ios_xe 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-2020-3421?
CyberStrike's AI-powered security agents can automatically detect CVE-2020-3421 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.
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