CVE-2021-1620
7.7 · HIGHOverview
CVE-2021-1620 is a high-severity vulnerability affecting cisco ios. It was published on September 23, 2021 and has a CVSS 3.1 base score of 7.7 (HIGH).
This vulnerability has a CVSS 3.1 base score of 7.7, rated HIGH. It can be exploited remotely over the network. Some level of privileges is required for exploitation.
Technical Description
A vulnerability in the Internet Key Exchange Version 2 (IKEv2) support for the AutoReconnect feature of Cisco IOS Software and Cisco IOS XE Software could allow an authenticated, remote attacker to exhaust the free IP addresses from the assigned local pool. This vulnerability occurs because the code does not release the allocated IP address under certain failure conditions. An attacker could exploit this vulnerability by trying to connect to the device with a non-AnyConnect client. A successful exploit could allow the attacker to exhaust the IP addresses from the assigned local pool, which prevents users from logging in and leads to a denial of service (DoS) condition.
Remediation
Check the references section for vendor advisories and patches from cisco. Update ios 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-2021-1620?
CVE-2021-1620 is a high-severity vulnerability affecting cisco ios. It was published on September 23, 2021 and has a CVSS 3.1 base score of 7.7 (HIGH).
How severe is CVE-2021-1620?
This vulnerability has a CVSS 3.1 base score of 7.7, rated HIGH. It can be exploited remotely over the network. Some level of privileges is required for exploitation.
How do I fix or remediate CVE-2021-1620?
Check the references section for vendor advisories and patches from cisco. Update ios 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-2021-1620?
CyberStrike's AI-powered security agents can automatically detect CVE-2021-1620 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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