CVE-2021-34767
7.4 · HIGHOverview
CVE-2021-34767 is a high-severity vulnerability affecting cisco ios_xe. It was published on September 23, 2021 and has a CVSS 3.1 base score of 7.4 (HIGH).
This vulnerability has a CVSS 3.1 base score of 7.4, rated HIGH. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.
Technical Description
A vulnerability in IPv6 traffic processing of Cisco IOS XE Wireless Controller Software for Cisco Catalyst 9000 Family Wireless Controllers could allow an unauthenticated, adjacent attacker to cause a Layer 2 (L2) loop in a configured VLAN, resulting in a denial of service (DoS) condition for that VLAN. The vulnerability is due to a logic error when processing specific link-local IPv6 traffic. An attacker could exploit this vulnerability by sending a crafted IPv6 packet that would flow inbound through the wired interface of an affected device. A successful exploit could allow the attacker to cause traffic drops in the affected VLAN, thus triggering the DoS condition.
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-2021-34767?
CVE-2021-34767 is a high-severity vulnerability affecting cisco ios_xe. It was published on September 23, 2021 and has a CVSS 3.1 base score of 7.4 (HIGH).
How severe is CVE-2021-34767?
This vulnerability has a CVSS 3.1 base score of 7.4, 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-2021-34767?
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-2021-34767?
CyberStrike's AI-powered security agents can automatically detect CVE-2021-34767 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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