What’s Vulnerable › Vulnerabilities

CVE-2020-3220: Cisco IOS XE Software IPsec VPN Denial of Service Vulnerability

• Severity: medium (CVSS 6.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2020-06-03 · updated 2026-06-17
• Weakness: CWE-345

Description

A vulnerability in the hardware crypto driver of Cisco IOS XE Software for Cisco 4300 Series Integrated Services Routers and Cisco Catalyst 9800-L Wireless Controllers could allow an unauthenticated, remote attacker to disconnect legitimate IPsec VPN sessions to an affected device. The vulnerability is due to insufficient verification of authenticity of received Encapsulating Security Payload (ESP) packets. An attacker could exploit this vulnerability by tampering with ESP cleartext values as a man-in-the-middle.

Affected products

• Cisco IOS XE: 16.4.1, 16.4.2, 16.4.3, 16.5.1, 16.5.1a, 16.5.1b (+62)

References

• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxe-vpn-dos-edOmW28Z
• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxe-vpn-dos-edOmW28Z

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