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CVE-2020-3399: Cisco IOS XE Wireless Controller Software for the Catalyst 9000 Family CAPWAP Denial of Service Vulnerability

• Severity: high (CVSS 8.6 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2020-09-24 · updated 2026-06-17
• Weakness: CWE-126

Description

A vulnerability in the Control and Provisioning of Wireless Access Points (CAPWAP) protocol processing of Cisco IOS XE Software for Cisco Catalyst 9800 Series Wireless Controllers could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition of an affected device. The vulnerability is due to insufficient input validation during CAPWAP packet processing. An attacker could exploit this vulnerability by sending a crafted CAPWAP packet to an affected device, resulting in a buffer over-read. A successful exploit could allow the attacker to cause the affected device to crash and reload, resulting in a DoS condition on the affected device.

Affected products

• Cisco IOS XE: 16.12, 16.12.1s, 16.12.2

References

• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-capwap-dos-ShFzXf
• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-capwap-dos-ShFzXf

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