CVE-2020-3125: Cisco Adaptive Security Appliance Software

Critical severity, CVSS 9.8. EPSS: 2.4% chance of exploitation in the next 30 days.

A vulnerability in the Kerberos authentication feature of Cisco Adaptive Security Appliance (ASA) Software could allow an unauthenticated, remote attacker to impersonate the Kerberos key distribution center (KDC) and bypass authentication on an affected device that is configured to perform Kerberos authentication for VPN or local device access. The vulnerability is due to insufficient identity verification of the KDC when a successful authentication response is received. An attacker could exploit this vulnerability by spoofing the KDC server response to the ASA device. This malicious response would not have been authenticated by the KDC. A successful attack could allow an attacker to bypass Kerberos authentication.

Affected products

• Cisco Adaptive Security Appliance Software: from 9.8, before 9.8.4.15 (fixed in 9.8.4.15); from 9.9, before 9.9.2.66 (fixed in 9.9.2.66); from 9.10, before 9.10.1.37 (fixed in 9.10.1.37); from 9.12, before 9.12.3.2 (fixed in 9.12.3.2); from 9.13, before 9.13.1.7 (fixed in 9.13.1.7)
• Cisco ASA 5505 Firmware: version 9.10(1.220) only
• Cisco ASA 5510 Firmware: version 9.10(1.220) only
• Cisco ASA 5512-X Firmware: version 9.10(1.220) only
• Cisco ASA 5515-X Firmware: version 9.10(1.220) only
• Cisco ASA 5520 Firmware: version 9.10(1.220) only
• Cisco ASA 5525-X Firmware: version 9.10(1.220) only
• Cisco ASA 5540 Firmware: version 9.10(1.220) only
• Cisco ASA 5545-X Firmware: version 9.10(1.220) only
• Cisco ASA 5550 Firmware: version 9.10(1.220) only
• Cisco ASA 5555-X Firmware: version 9.10(1.220) only
• Cisco ASA 5580 Firmware: version 9.10(1.220) only
• Cisco ASA 5585-X Firmware: version 9.10(1.220) only

Published 2020-05-06. Last modified 2026-06-17.