CVE-2020-3303: Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software IKEv1 Denial of Service Vulnerability

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2020-05-06 · updated 2026-08-11
Weakness: CWE-399

Description

A vulnerability in the Internet Key Exchange version 1 (IKEv1) feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. The vulnerability is due to improper management of system memory. An attacker could exploit this vulnerability by sending malicious IKEv1 traffic to an affected device. A successful exploit could allow the attacker to cause a DoS condition on the affected device.

Affected products

Cisco Adaptive Security Appliance: before 9.6.4.36 — fixed in 9.6.4.36
Cisco ASA Software: from 9.7 before 9.8.4.10; from 9.9 before 9.10.1.30; from 9.12 before 9.12.2.9 — fixed in 9.10.1.30, 9.12.2.9, 9.8.4.10
Cisco Firepower Threat Defense Software: before 6.3.0.5; from 6.4.0 before 6.4.0.6 — fixed in 6.3.0.5, 6.4.0.6

How to fix

Upgrade to a fixed version: Cisco Adaptive Security Appliance 9.6.4.36; Cisco ASA Software 9.10.1.30, 9.12.2.9, 9.8.4.10; Cisco Firepower Threat Defense Software 6.3.0.5, 6.4.0.6. Check the vendor advisory for mitigations.

References

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